System, method and article of manufacture for creating an object oriented component having multiple bidirectional ports for use in association with a java application or applet

ABSTRACT

Method, system and article of manufacture for creating an object oriented component having multiple bidirectional ports for use with an object oriented based applet or application. The component&#39;s ports are all first initialized to a predetermined value and thereafter polled to determine if an input has been coupled to any one of the ports. If it has not, polling continues. If an input is present, all of the component&#39;s remaining ports are set to output the same type and value as that of the input. Where appropriate, a check is made to determine if a saved state of the component exists. if it does, the component is initialized to the state type and value rather than the predetermined type and value. When the input is removed, the component ports are all reinitialized to the predetermined type and value and polling for a new input commences.

COPYRIGHT NOTIFICATION

Portions of this patent application include materials that are subjectto copyright protection. The copyright owner has no objection to thefacsimile reproduction by anyone of the patent document itself, or ofthe patent application, as it appears in the files of the United StatesPatent and Trademark Office, but otherwise reserves all copyright rightswhatsoever in such included copyrighted materials.

FIELD OF THE INVENTION

This invention generally relates to improvements in computer systemsand, more particularly, to an improved object oriented component systemhaving multiple bidirectional ports, which ports can be set to mirrorthe input type and value applied to one of the ports.

BACKGROUND OF THE INVENTION

Object oriented based programming (OOP) is probably the most arresting,stimulating and intriguing aspect of programming in today's softwareworld. Although it has been available for some time in languages such asSimula and SmallTalk and recently in C++ and Java, OOP has only recentlytaken hold as the hoped for solution to closing the gap between thetheoretical capability of hardware and the general performance ofsoftware while simultaneously solving problems left over from priorsoftware development approaches.

In the past, programming development which began with a single procedureapproach, evolved to modular programming, went from there to structuredprogramming and then branched off into computer aided softwareengineering (CASE) and program generators. All of these methodologies,while solving some or many of the difficulties inherent in priorapproaches, introduced their own limitations and inefficiencies. Programbloat, data corruption and "spaghetti" code were but a few of theproblems that were caused or left unsolved by the aforementionedsoftware development approaches.

In the early days of procedural programming, the programmer calledlibraries provided by the operating system to perform certain tasks, butbasically the program executed down the page from start to finish, andthe programmer was solely responsible for the flow of control. This wasappropriate for printing out paychecks, calculating a mathematicaltable, or solving other problems with a program that executed in justone way.

The development of graphical user interfaces began to turn thisprocedural programming arrangement inside out. These interfaces allowthe user, rather than program logic, to drive the program and decidewhen certain actions should be performed. Today, most personal computersoftware accomplishes this by means of an event loop which monitors themouse, keyboard, and other sources of external events and calls theappropriate parts of the programmer's code according to actions that theuser performs. The programmer no longer determines the order in whichevents occur. Instead, a program is divided into separate pieces thatare called at unpredictable times and in an unpredictable order. Byrelinquishing control in this way to users, the developer creates aprogram that is much easier to use. Nevertheless, individual pieces ofthe program written by the developer still call libraries provided bythe operating system to accomplish certain tasks, and the programmermust still determine the flow of control within each piece after it'scalled by the event loop. Application code still "sits on top of" thesystem.

Even event loop programs require programmers to write a lot of code thatshould not need to be written separately for every application. Theconcept of an application framework carries the event loop conceptfurther. Instead of dealing with all the nuts and bolts of constructingbasic menus, windows, and dialog boxes and then making these things allwork together, programmers using application frameworks start withworking application code and basic user interface elements in place.Subsequently, they build from there by replacing some of the genericcapabilities of the framework with the specific capabilities of theintended application.

Into to this breach, entered Object-Oriented Programming (OOP)techniques which involve the definition, creation, use and destructionof "objects." Objects are self-sufficient software entities comprisingdata elements and routines, or functions, sometimes called methods,which are used to manipulate the data elements. The object's data andrelated functions are treated by the software as an entity and they canbe created, used and deleted as if they were a unitary item. Together,the data and functions enable objects to model virtually any real-worldentity in terms of its characteristics, which can be represented by thedata elements, and its behavior, which can be represented by its datamanipulation functions. In this way, objects can model concrete thingslike people and computers, and they can also model abstract conceptslike numbers or geometrical designs.

Objects are defined by creating "classes" which are not per se objectsthemselves, but which act as templates that instruct a compiler how toconstruct an actual object. A class may, for example, specify the numberand type of data variables and the steps involved in the functions whichmanipulate the data. An object is actually created in the program bymeans of a special function called a constructor which uses thecorresponding class definition and additional information, such asarguments provided during object creation, to construct and initializethe object and its data members. Likewise objects are destroyed by aspecial function called a destructor. Objects are employed by usingtheir data and invoking their functions to accomplish a task.

The concept of an object is predicated on and the benefits ofobject-oriented programming techniques arise from the use of three basicprinciples; those of encapsulation, polymorphism and inheritance. Theseprinciples work in conjunction with objects as described below. It isnoteworthy to distinguish between an object and a class of objects. Aclass is a type definition or template used to create objects inprograms. The objects so created are then merely each a single instanceof the class of objects, which is often just called a class. A class hasno memory or behavior of its own except to serve as the blueprint fromwhich objects can be created.

An object is a self-sufficient component that includes both data andfunction. An object is of the same type as the class from which it hasbeen derived. Objects are said to be instantations of their class anduse memory for their data and functions, unlike the class templateitself which does not.

Objects can be designed to hide, or encapsulate, all, or a portion of,their internal data structure and internal functions. OOP also allows aprogrammer to create an object that is a part of another object andthereby define assemblies and sub-assemblies, as may be required by aprogram or the situation or item it is modeling.

More particularly, during program design, a program developer can defineobjects in which all or some of the data variables and all or some ofthe related functions are considered "private" or made available for useonly by the object itself. Other data or functions can be declared"public" or available for use by other objects or programs.

Further, access to private variables by other objects or programs can becontrolled by defining public functions for an object which access theobject's private data. The public functions form a controlled andconsistent interface between the private data and the "outside" world.Any attempt to write program code which directly accesses the privatevariables causes the compiler to generate an error during programcompilation which error stops the compilation process and prevents theprogram from being run.

Polymorphism is capability to conceal the different implementationsbehind a common interface. This means that separate objects of the sameclass can have different internal functions and data and implementreceived messages differently, but still produce uniform or consistentresults. For example, an addition function may be defined as variable Aplus variable B (A+B) and this same format can be used whether variablesA and B represent numbers, characters or monetary units such as dollarsand cents. However, the actual program code which performs the additionmay differ widely depending on the type of variables that comprise A andB. Polymorphism allows three separate objects that employ differentfunction definitions to be written, one for each type of variable(numbers, characters and dollars). After the functions have beendefined, a program can later refer to the addition function by itscommon format (A+B) and, during compilation, the OOP based compiler willdetermine which of the three functions needs to be used by examining thevariable types. The compiler will then substitute the proper functioncode in the object it compiles. Polymorphism allows similar functionsthat produce analogous results to be "grouped" in the program sourcecode to produce a more logical and clearer program flow.

The third principle which underlies object-oriented programming is thatof inheritance. Inheritance allows program developers to easily reusepre-existing programs or portions thereof to avoid creating softwarefrom scratch. The principle of inheritance allows a software developerto declare classes (and the objects which are later created from them)as related. Specifically, classes may be designated as subclasses ofbase classes. A subclass "inherits" and has access to all of the publicfunctions of its base classes just as if these functions appeared in thesubclass. Alternatively, a subclass can override some or all of itsinherited functions merely by defining a new function with the same form(overriding or modification does not alter the function in the baseclass, but merely modifies the use of the function in the subclass). Thecreation of a new subclass which has some of the functionality (withselective modification) of another class allows software developers toeasily customize existing code to meet their particular needs whilestill taking advantage of reusing prior, usually debugged and wellbehaved code, rather than having to write and qualify new code of theirown.

By utilizing the concepts of encapsulation, inheritance andpolymorphism, an object can be made to accurately and independentlyrepresent just about anything in our world, real or simulated. In fact,the limits of our logical perceptions of such representation is the onlyrestraint on the kinds of things that can become objects inobject-oriented software. Some typical categories are as follows:

Objects can represent physical objects, such as airplanes in an airtraffic control system, components in a stereo or television system,balance sheet and income statement elements in a fundamental analysiscompany business model, or stars in the simulated night sky on displayat a planetarium;

Objects can represent elements of the computer-user environment such aswindows, scrollbars, sliders, menus or other graphical items;

An object can represent a collection of data, such as a personnel fileor a table of the latitudes and longitudes of cities; or

An object can represent user-defined data types such as time, angles,and complex numbers, functions or points on the plane.

While object-oriented programming offers significant improvements overother programming concepts in the design and development of programs,program development and program development tools, even within an OOPenvironment, still require significant outlays of time and effort. Thisis particularly true where the developer has to write a significantamount of code from scratch and is unable to take full advantage of thebenefits of object oriented programming. The ability of developmenttools to negate or reduce the need to write code in the traditionalsense and permit a developer to concentrate on development and visuallyinteract with an enriched development tool is the focus and goal of thepresent invention.

It is usually the case that proponents of a particular type ofprogramming language or of a specific language of that type are bestable to advance their cause and the popularity and vitality of thelanguage type or specific implementation or dialect of the language theysupport.

This is usually done by directly or indirectly providing appropriatetools that make use of the language type or a specific implementation ofthe language easy, practical and efficient. Visual Basic and Visual C++are examples of two current programming environments with an objectoriented foundation that have been developed and made available forprogrammers to use in creating applications for the Windows 3.x, Windows95 and Windows NT platforms. While Visual Basic and Visual C++undoubtedly make program development easier by including tools, calledWizards, that relieve the programmer of the necessity to write theunderlying Basic or C++ code needed to create and implement such typicalgraphical user interface (GUI) elements as scrollbars, sliders, buttonsor dialog boxes and to define their properties, these tools do not gofar enough in easing the programmer's development burden. For example,it is still necessary in either Visual Basic and Visual C++ for theprogrammer to write code that defines and controls the interrelationshipof the elements selected for use in the program under development or tootherwise manually intercede in the object based "point and click" or"drag and drop" aspects of this program development process.

This is true in the development of general OOP based applications andalso in development environments for creating Applets in a JAVA system.As the Java system and applet creation becomes more widely used, theneed to simplify the development of these applications becomesdesirable. In addition, while the developer in these prior art visualprogramming environments is given a Wizard that writes the underlyingcode to make an event involving one or more of the selected elementsoccur, the ability to simultaneously view and experience thatinterrelationship is not provided.

It would be desirable to provide the tool's objects or components with acomponent that can function as a multiplexor wherein an input applied toone of the components bidirectional ports is dynamically duplicated asan output on all the remaining ports of the component.

SUMMARY OF THE INVENTION

The present invention provides a programming environment and appropriatetools and components therefor that promote greater ease of use than ispresently available in typical programming environments. and wherein anobject

The present invention also provides such a multiport component havingmultiple bidirectional ports that can be set to duplicate an inputthereto on its remaining ports.

The present invention additionally initializes such a multiportcomponent to a predetermined type and value or to the type and value ofa saved state if one exists.

The present invention further provides the user with means to utilizesuch a component in an effective, non-intrusive manner.

The above objectives are achieved by utilizing an object orientedcomponent having multiple bidirectional ports that is adapted for usewith an object oriented based applet or application. The component'sports are all first initialized to a predetermined value and thereafterpolled to determine if an input has been coupled to any one of theports. If it has not, polling continues. If an input is present, all ofthe component's remaining ports are set to output the same type andvalue as that of the input. Where appropriate, a check is made todetermine if a saved state of the component exists, if it does, thecomponent is initialized to the state type and value rather than thepredetermined type and value. When the input is removed, the componentports are all reinitialized to the predetermined type and value andpolling for a new input commences.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of the invention may be betterunderstood by referring to the following description in conjunction withthe accompanying drawings, in which:

FIG. 1 is a block schematic diagram of a typical computer system, forexample, a personal computer system on which inventive object orientedbased programming tools or development environment functions can operatein accordance with the present invention;

FIG. 2 depicts a block diagram of a Java platform development tool inaccordance with a preferred embodiment;

FIG. 3 illustrates a block diagram showing the initialization processfor the Visual Java Tool applet in accordance with a preferredembodiment;

FIG. 4A shows an example of an illustrative World Wide Web home page asloaded by a Java enabled browser in accordance with a preferredembodiment;

FIG. 4B illustrates the same web page with its main pull-down menuactivated in accordance with a preferred embodiment;

FIG. 4C depicts the "Open File" pull-down menu of the home page shown inFIG. 4B in accordance with a preferred embodiment;

FIG. 4D shows the VJ Tool applet after it has been initialized and isready to run in accordance with a preferred embodiment;

FIG. 5 illustrates the physical or end user view screen portion inaccordance with a preferred embodiment;

FIG. 6 shows the creation of a scrollbar which will be used to indicateCentigrade temperatures in an example of how the present invention canbe utilized in accordance with a preferred embodiment;

FIG. 6A is a functional block diagram depicting socialization of newcomponents in accordance with a preferred embodiment.

FIG. 7 visually describes an example of marqueing or sizing of avertical scrollbar in accordance with a preferred embodiment;

FIG. 8 depicts another example of marqueing or adjusting the size of avertical scrollbar to a shorter, slightly wider, outline in accordancewith a preferred embodiment;

FIG. 9 illustrates an example of a scrollbar object matching the sameobject in FIG. 8, but created in the logical view in accordance with apreferred embodiment;

FIG. 10 shows the two pin value setting and getting capability of thescrollbar of FIG. 8 in accordance with a preferred embodiment;

FIG. 11 illustrates the addition of a second vertical scrollbar thatwill be set to track the range of the Fahrenheit temperature scale inaccordance with a preferred embodiment;

FIG. 11A is a flowchart of the detailed logic of the editor component inaccordance with a preferred embodiment,

FIG. 12 depicts how label text is added to the scrollbars of FIG. 11 tolabel the scrollbar in accordance with a preferred embodiment;

FIG. 13 shows how text from a label editor has been placed as a labelabove the first scrollbar of FIG. 11 in accordance with a preferredembodiment;

FIG. 13A illustrates a flowchart for the process by which the bicopycomponent shown in FIG. 13 functions in accordance with a preferredembodiment;

FIG. 14 illustrates the addition and use of splitters in the logicalview in accordnace with in accordance with a preferred embodiment;

FIG. 15 shows the addition of a calculator object to the logical view inaccordance with a preferred embodiment;

FIG. 16 depicts an additional calculator and the interconnections ofseveral objects to achieve the appropriate Centigrade/Fahrenheitrelationship between scrollbars of FIG. 11 in accordance with apreferred embodiment;

FIG. 16A is a flowchart of the detailed logic for port connection inaccordance with a preferred embodiment;

FIG. 17 shows the final result of the conecteded scrollbars with correctFahrenheit and Centigrade temperatures shown in the text fields inaccordance with a preferred embodiment;

FIG. 18 is a diagram in block format of an arrangement adapted toprovide collaboration between components or portions of components of anapplet as designated by the user in accordance with a preferredembodiment;

FIG. 19 presents a flowchart of the collaboration process in accordancewith a preferred embodiment;

FIG. 20 illustrates a screen with the logical view in accordance with apreferred embodiment;

FIG. 21 illustrates a screen with the logical and physical viewpreparing a hierarchial component in accordance with a preferredembodiment;

FIG. 22 illustrates a screen with a connection made for playing a soundin accordance with a preferred embodiment;

FIG. 23 illustrates an edit screen for a folder component utilized toprepare a hierarchial component in accordance with a preferredembodiment;

FIG. 23A is a functional block diagram depicting editing of a folder toprepare a hierarchical component in accordance with a preferredembodiment.

FIG. 24 illustrates a hierarchial component creation customization inaccordance with a preferred embodiment; and

FIG. 25 illustrates the completed physical view of a hierarchialcomponent in accordance with a preferred embodiment.

DETAILED DESCRIPTION

The invention is preferably practiced in the context of a suitableoperating system resident on a workstation or desktop computer, such asa SUN, IBM, PS/2, or Apple, Macintosh, computer. A representativehardware environment is depicted in FIG. 1, which illustrates a typicalconfiguration for a computer system 100 that can be utilized to practicethe subject invention. The computer 100 is controlled by a centralprocessing unit 102 (which may be a conventional microprocessor). Anumber of other units, all interconnected via a system bus 108, areprovided to accomplish specific tasks. Although a particular computermay only have some of the units illustrated in FIG. 1, or may haveadditional components not shown, most computers will include at leastthe units shown.

Specifically, computer system 100 shown in FIG. 1 includes a randomaccess memory (RAM) 106 for temporary storage of information, a readonly memory (ROM) 104 for permanent storage of the computer'sconfiguration and basic operating commands and an input/output (I/O)adapter 110 for connecting peripheral devices such as a disk drive unit113 and printer 114 to the bus 108, via cables 112 and 115,respectively. A user interface adapter 116 is also provided forconnecting input devices, such as a keyboard 120, and other knowninterface devices including a microphone 124, a mouse 126 and a speaker128, to the bus 108. Visual output is provided by a display device 122,such as a video monitor, which is connected via display adapter 118 tobus 108. Lastly, a communications adapter 134, connected to bus 108,provides access to a network 136.

The computer 100 has resident thereon and its basic operations arecontrolled and coordinated by operating system software such as the SUNSolaris, Windows/95, Windows NT or the Java OS operating system. Forpurposes of the preferred embodiment as described herein, regardless ofthe operating system being used, computer 100 is provided, at the veryleast, with the Java run time environment and an optional Just-In-Time(JIT) Java compiler.

In a preferred embodiment, the invention is implemented in the Javaprogramming language, relying substantially on its object-orientedprogramming techniques. Java is a compiled language, that is, Java basedprograms are typically written in a human-readable script which scriptis eventually provided as input to another program called a compiler.The compiler generates a byte code version of the script that can beloaded into, and directly executed by, any computer which contains aJava virtual machine. Java objects are compiled to class files thatinclude bytecodes representative of the original source code programwith references to methods and instance variables of the Java objects.The bytecodes are not specific to particular machines or operatingsystems and don't have to be recompiled or rearranged to run ondifferent hardware/software platforms. Rather, the bytecodes can be runin the Java Virtual Machine or passed to a (JIT) compiler that convertsthem into native code for a target platform on the fly.

This means that the original Java application or applet bytecode, whichisn't specific or native to any one hardware platform or architecture,can be run without recompilation on any hardware or software platformthat has a Java Run-Time Environment. In other words, a Java program'snative architecture is the Java VM which is or will soon be available inboth software and hardware implementations, making Java applications andapplets multi-platform capable as long as the target system is Javaenabled. As described below, the Java language has certaincharacteristics which allow a software developer to easily use and reuseprograms written by himself or others while still providing a reason forreuse of programs or portions of programs to prevent their destructionor improper use.

Sun's Java language has emerged as an industry-recognized language, notonly for "programming the Internet, but also as " . . . a seriousprogramming language capable of tackling the most sophisticated businessapplications." Sun defines Java as: "a simple, object-oriented,distributed, interpreted, robust, secure, architecture-neutral,portable, high-performance, multithreaded, dynamic, buzzword-compliant,general-purpose programming language. Java supports programming for theInternet in the form of platform-independentJava applets." Java appletsare small, specialized applications that comply with Sun's JavaApplication Programming Interface (API) allowing developers to add"interactive content" to Web documents (e.g. simple animation, pageadornments, basic games, etc.). Applets execute within a Java-compatiblebrowser (e.g. Netscape Navigator) by copying code from the server toclient. From a language standpoint, Java's core feature set is based onC++. Sun's Java literature states that Java is basically "C++, withextensions from Objective C for more dynamic method resolution".

Another technology that has function and capability similar to JAVA isprovided by Microsoft and its ActiveX technology, to give developers andWeb designers the wherewithal to build dynamic content for the Internetand personal computers. ActiveX runs only the so-called Wintel platform(a combination of a version of Windows and an Intel microprocessor), ascontrasted with Java which is a compile once, run anywhere language.

ActiveX includes tools for developing animation, 3-D virtual reality,video and other multimedia content. The tools use Internet standards,work on multiple platforms, and are being supported by over one hundredcompanies. The group's building blocks are called ActiveX Controls,small, fast components that enable developers to embed parts of softwarein hypertext markup language (HTML) pages. ActiveX Controls work with avariety of programming languages including Microsoft's Visual C++,Borland's Delphi, Microsoft's Visual Basic programming system and, inthe future, Microsoft's development tool for Java, code named "Jakarta."ActiveX Technologies also includes ActiveX Server Framework, allowingdevelopers to create server applications. One of ordinary skill in theart will readily recognize that ActiveX and ActiveX components could besubstituted for JAVA and its components as their use is described hereinwithout undue experimentation to practice the invention.

Further explanation of the Java programming language, itscharacteristics and advantages is not deemed necessary. Java is nowwell-known and many articles and texts are available which describe thelanguage in great detail. In addition, compilers and development kitsare commercially available from several vendors including SunSoft Inc.,Borland International, Inc. and Microsoft Corporation. Accordingly, forreasons of brevity and clarity, additional details of the Java languageand the operation of the Run-Time Environment or the JIT compilers willnot be discussed further in herein since this information can be readilyobtained elsewhere. One appropriate source can be found in Gosling, Joy& Steele, The Java Language Specification (1996), the disclosure ofwhich is hereby incorporated by reference. Another source for Java VMinformation is Sun Microsystems' Java Virtual Machine Specification,Release 1.0 Beta DRAFT (Aug. 21, 1995), the disclosure of which is alsohereby incorporated by reference.

The arrangement described above concerning the running of Java appletsand applications is illustrated in FIG. 2. This block diagram shows howa Java application or applet can be run on one or more hardware/softwareplatform combinations. The applets can be obtained, along with thestatic information (text and/or graphics) of the web page they areresident on, by either an ordinary web browser or one that is Javaenabled. If the applet is obtained by a non-Java enabled browser, asdepicted in block 202, it is passed via connection 203 to the JavaRun-Time Environment 206 where the applet code is compiled into Javabytecode class files. The bytecode is then checked for security purposesby the bytecode verifier and then run on the Java VM by the bytecodeinterpreter to yield Java derived code that can be input to the optionalJIT compiler 208 via connection 207 for conversion to platform nativecode.

Java source is compiled into bytecodes in an intermediate form insteadof machine code (like C, C++, Fortran, etc.) to enable and facilitateportability. The bytecodes execute on any machine with a bytecodeinterpreter. Thus, Java applets and applications can and do run on avariety of client machines. Further, since the bytecodes are compact anddesigned to transmit efficiently over a network, Java enhances apreferred embodiment with universal clients and server-centric policies.

The output of the JIT compiler 208 is passed therefrom via connection209 to a target platform 210. Target platform 210 could be, for example,a Windows combination, a Macintosh System 7/PowerPC combination or aUnix/RISC combination. If the Operating System (OS) of the targetplatform is Java enabled, that is, if it includes its own Java Run-Timeenvironment, then the Environment 206 output could be passed directlyvia connector 211 to the target platform 210 avoiding the Java JITcompiler 208 whose services would not be needed.

Alternatively, if an applet is obtained by a Java enabled browser (suchas Sun's HotJava, Netscape's Navigator 3.0 or Microsoft's InternetExplorer 3.0) which includes and has already installed the Java Run-TimeEnvironment on the computer where it resides, there is no need toutilize the separate Environment 206. Applets so captured are passed viaconnector 213 through by the Java enabled browser at 212 to the JavaEnvironment, also logically part of block 212, where such applets arehandled as described above in connection with function block 206.Lastly, stand-alone Java applications are passed directly to the JavaEnvironment block 206 where they are handled and processed in a similarmanner to the Java applets. The Java applications do not need to beobtained nor do they work in conjunction with a browser. However, if aJava enabled browser is loaded on the developer's hardware, as isprobable, a Java application can be passed directly to the browser offunction block 212 via connector 215 and handled in the same manner asan applet would have been.

A preferred embodiment of an applet that will be known as the VisualJava Tool (or VJ Tool hereafter) takes the concept of objects andapplies it through the entire development system to provide adevelopment or authoring tool that is robust, easy to use and one thatminimizes the amount of code a developer needs to write. VJ Tool isdescribed herein in the context of an applet, but as it has been noted,VJ Tool could also be provided as a full application and handled in themanner described above. The user of VJ Tool would not have to beknowledgeable about Java or OOP and could build or create a Java appletor application from scratch just by using VJ Tool in the mannerdescribed herein.

FIG. 3 is a block diagram that shows the initialization process for theVisual Java Tool applet in accordance with a preferred embodiment of theinvention. The applet 302 is seen by a Java enabled browser 304, such asSun's HotJava or Netscape's Navigator, via link 305 and then downloadedvia connection 303 to the client computer on which the browser resides.Alternatively, the VJ Tool can be obtained from local storage as anapplication. When browser 304 is activated, it also initializes andmakes the Java Run-Time Environment 306 active thereby initiating andreadying the Java Virtual Machine for the eventual arrival of an applet.

Once obtained from its web page or local storage, the VJ Tool is itselfinitialized as shown in block 308 and made ready for interaction with auser, see block 310. Initialization of the applet includesinitialization of the desktop (VJContainer) and the web page view(VJDocument). VJContainer and VJDesktop are tightly coupled. VJContaineris a container API. The details of applet initialization for VJ Tool areincluded in VJContainer and VJDesktop.

For each component, a template is initially used to define theparticular characteristics of the component. The template includes astart, stop, initialize, destroy, connect, disconnect, customize (edit),save, load and one or more component specific task methods. Thesemethods are customizable for each of the components so that thesliderbar component has a different disconnect method then a buttoncomponent. ##SPC1##

The source code enabling the container editor for modifying propertiesof the container is presented below. When a new component isinstantiated on either the physical or logical display, an optionalcustomizer (edit) window is presented if a containerEditor method isdefined for the component. The customizer (edit) window is defined inthe template as a method corresponding to the customizer (edit) method.The method contains the logic facilitating the dynamic definition ofproperties of the component and the update of the properties based onuser interaction with the customizer (edit) window. ##SPC2##

VJ Tool dispatches start stop and init messages to all active instancesof components as start(), stop() and init(). When VJ is loading, we wantto have the user wait until that process is completed, so VJ Tool willignore events and a splash sheet with a warning message is displayedthat says no action will be possible until loading is completed. Once VJTool is loaded and initialized completely, the warning screen is droppedand user interaction is enabled.

The initialization process initializes and enables the logical view andthe physical view. The initialization processing includes VJ Tool's datastructures and palettes, which comprise "primitive" or basic buildingblock components coded entirely in Java. Once initialization iscompleted, the cut, paste, select all, move, drag, drop, point, andother functions are active. These functions associated with the VJ Toolmenu bars are defaulted from the VJContainer class. The palettes andmenus are created from VJDesktop.

VJ Tool then invokes user requests and such actions as may beappropriate thereto, as indicated in block 312. Once all requests havebeen satisfied, VJ Tool cycles back through link 314 and waits forsubsequent user requests. If there are no further requests to be carriedout, the user exits via block 316.

FIG. 4A shows an example of a World Wide Web home page that is displayedwhen the Netscape Navigator is invoked in accordance with a preferredembodiment. If this page had included a Java enabled applet, that appletwould have been downloaded and activated as soon as the user clicked onit. Alternatively, an applet could be locally resident and thus bedirectly available. FIG. 4B illustrates the same web page with its mainpull-down menu activated. FIG. 4C depicts the "Open File" pull-down menuof the home page shown in FIG. 4B. Note that the files found in thelocal file "saul.htm" include the applet called "DemoRelease", which isactually a back level version of VJ Tool, ready to select and run.

FIG. 4D shows the VJ Tool applet after it has been initialized and isready to run. VJ Tool comes up on the user's screen after beinginitialized and deployed with two main views as shown in FIG. 4D. Theseviews are equivalent to the status depicted by block 310 in FIG. 3.Window 402 shows the active VJ Tool desktop, in particular, its logicalview 402. Logical view 402, also called the document view, is createdfrom VJDocument. Window segment 404 is the right hand portion of thebase home page shown in FIGS. 4A, 4B and 4C. The other view, the userphysical view is shown in FIG. 5. ##SPC3##

The palette in logical view 402, as shown in FIG. 5, is provided with aseries of components that are instantiated from the componentVJContainer. FIG. 5 illustrates the physical view or end user viewscreen portion in accordance with a preferred embodiment of the VJ Tool.

FIG. 5 also shows the physical view 500 of the VJ desktop. The logicalview 402 is in the foreground on the right hand side of the drawing,while the physical view 500 is in the background on the left side of thescreen. Physical view 500 is provided with palette containers 502 to 530as follows: 502 is a select cursor button; 504 is a simple AWT label;506 is a simple AWT text field; 508 is a simple AWT text area; 510 is asimple AWT button; 512 is a simple AWT checkbox; 514 is a simple AWTchoice box; 516 is a simple AWT list; 518 is a simple AWT horizontalscroll bar; 520 is a simple AWT vertical scroll bar; 522 is a simple barchart; 524 is a simple spreadsheet; 526 is a simple AWT panel; 528 is acalendar; and 530 is an animator.

Logical view 402 is provided with palette containers 540 to 572 asfollows: 540 is a select cursor button; 542 is a VJ folder or container;544 is an adder; 546 is a bicopy component. The bicopy component acts asa multiplexor so that whatever is input on one pin of a bicopy elementis output on its other pins. 548 is a test for equals; 550 is a constant(e.g. -1 or 3.1457 or "abc"); 552 is a random number generator; 554 is acounter; 556 is an URL opener; 558 is a splitter used to connectinput/output pins to components that are either input or outputelements; 560 is a two-dimensional grapher; 562 is a three-dimensionalgrapher; 564 is a delta three-dimensional grapher; 566 is an URL textviewer; 570 forwards input from any one of an element's input pins to anoutpin pin thereof; 572 is a calculator; and 574 is a sound player. AWTis the Abstract Windowing Toolkit and contains the objects utilized forproviding basic windowing functions in accordance with a preferredembodiment.

The components of logical view 402 and physical view 500 can be dropped,respectively, from their palettes into the view they are associatedwith. Moving the cursor over any component causes a short description ofthat component to appear in the logical view.

FIGS. 6 through 17 illustrate an example of a VJ Tool used to quickly,efficiently and accurately create an applet derived mini applicationthat does not require the VJ Tool user to write a single line of code.Unlike other "visual" tools currently available, VJ Tool is a "point andclick" and "drag and drop" development environment in which thecomponents are all activate immediately. It is important to note that VJTool provides a "live" environment; that is, you can see modificationsyou make take hold or be applied as the component is utilized. Thephysical view results in corresponding changes in the logical view. Ifyou eliminate a component from the physical view, it disappears as wellfrom the logical page and if you change the properties of a component inthe physical view, its associated component in the logical view reflectsthat change as it is made. The components initialization method occurswhen the component is instantiated and the component immediatelycommunicates with the other components previously defined for thephysical and logical display.

The component's "liveness" refers to immediate activation of componentsas components are interactively added to the environment. The action ofthe components is analogous to a What You See Is What You Get (WYSIWIG)word processing environment in which immediate feedback of status andvalue information is available. So, for example, as a button is placedon the display, it is immediately available for connection to a playercomponent to display text or activate a multimedia presentation.

"Liveness" and "live", as used in this description, are terms employedto illustrate how the present invention promotes and permits immediatesocialization of new components, as they are instantiated or droppedinto either the logical or physical views, with existing components.This is achieved, as depicted in the functional block diagram of FIG.6A, by registering the component being instantiated with the VJ Kernelvia block 620. Registration, in turn, invokes an initialization methodin block 622 that appropriately personalizes the new component when itexecutes the logic associated with the initialization method, see block624, which can include the provision of an editor for the new componentif its properties are to editable. The new component can immediatelycommunicate or socialize with other components previously defined in thelogical and physical views as shown by block 626.

Liveness also indicates that the environment is tested as new componentsare instantiated. This means that immediate connections betweencomponents are permitted on the fly. There is no requirement that allpossible connections are tried first to insure that nothing blows up.The outcome of this capability is that design creation and trial areintegrated so that the results can be observed virtually at the sametime that the interconnection of components is made. As noted laterherein in connection with the description of FIG. 16, this is analogousto building a hardware prototype or test board by interconnecting,disconnecting and moving electronic components around the test boardwhile the power is left on. As will be shown by the following example ofFahrenheit and Centigrade conversion, there is immediate feedback ofcomponent status and value information. This makes VJ Tool, in essence,a WYSIWIG development environment.

The specific example shown in various stages in FIGS. 6 through 14depicts two scroll bars that have been adapted through use of VJ Tool todisplay conversions of Fahrenheit and Centigrade temperatures to eachother on a dynamic basis. This applet has been created in the physicalview and reflected in the logical view in accordance with a preferredembodiment of the present invention.

FIG. 6 shows the creation of a first scroll slider bar 602 which will beused to indicate Centigrade temperatures. This object has beeninstantiated by clicking on the vertical scroll bar component 520 andthen dragging and dropping the object to its FIG. 6 position in thephysical view 500. When scroll bar 602 is created, its editor, verticalscroll bar editor 604, pops up as a dialog box wherein the current,visible, maximum and minimum values of the scroll bar just crated aredisplayed and can be edited. As shown, scroll bar 602 has a currentvalue of fifty, it is showing only ten units of its total range whichvaries from a maximum of one hundred (boiling point) to a minimum ofzero (freezing point).

FIG. 7 is an example of marqueing or sizing the vertical scrollbar inaccordance with a preferred embodiment. This is done by using the mouseto drag the edges or handles 606, see FIG. 6, of scroll bar 604 untilthe desired scroll bar shape is achieved. The result of that action isshown in FIG. 7 where the original scroll bar has been lengthened andreduced in width to form scroll bar 604a. FIG. 8 illustrates anotherexample of adjusting the size of the vertical scrollbar 604a to ashorter, slightly wider, outline 604b. The logical view 402 can be seenin FIG. 8, where it remains in the background, available for use as maybe needed.

The source code for the VJScrollbar component is presented below.

    __________________________________________________________________________    import java.awt.*;    import java.util.*;    public class VJVScrollbar extends VJNode {    // Attributes of this component    public AWTVScrollbar bar;    static int instanceCount = 0;    vscrollbarEditor edit;    static Image normalImage;    static Image selectedImage;    final static String out = "out.sub.-- vsb.gif";    final static String in = "in.sub.-- vsb.gif";    final static String port0.sub.-- info = "for setting/getting.minimum    value";    final static String port0.sub.-- name = "Pin 0";    final static String port1.sub.-- info = "for setting/getting.maximum    value";    final static String port1.sub.-- name = "Pin 1";    final static String port2.sub.-- info = "for setting/getting the current    value";    final static String port2.sub.-- name = "Pin 2";    final static String url.sub.-- name = "hscrollbar.html";    final static String info.sub.-- name = "A simple AWT horizontal    scrollbar";    VJ vj;    intsend.sub.-- index0 = -1;    int request.sub.-- index0 = 0;    int send.sub.-- index1 = -1;    int request.sub.-- index1 = 0;    int send.sub.-- index2 = -1;    int request.sub.-- index2 = 0;    // Constructor    public VJVScrollbar(VJ v){     super(v);     vj = v;    VJNode dup( ) {     VJVScrollbar vj.sub.-- comp = new VJVScrollbar(vj);     try{    int i = x+40;    int j = y+40;    AWTVScrollbar t = new AWTVScroll.bar(vj.sub.-- comp);    vj.sub.-- comp.bar = t;    t.setValues(bar.getValue( ),bar.getVisible( ),bar.getMinimum(    ),bar.getMaximum( ));    vj.sub.-- comp.setNormalIcon(out);    vj.sub.-- comp.setSelectedIcon(in);    vj.sub.-- comp.setName("VScrollbar");    vj.sub.-- comp.setComponent((Component)t);    vj.sub.-- comp.setComponentURL(url.sub.-- name);    vj.sub.-- comp.setComponentInfo(info.sub.-- name);    vj.sub.-- comp.VJNodeInit(false,i,j,true);    vj.sub.-- comp.addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOut    put,VJPort.NorthLeftCenter);    // Pin 0    vj.sub.-- comp.addPort(port 1.sub.-- info,port 1.sub.-- name,VJPort.InputO    utput,    VJPort.NorthRightCenter); // Pin 1    vj.sub.-- comp.addPort(port2.sub.-- info, port2.sub.-- name,VJPort.InputOu    tput,VJPort.SouthCenter);    // Pin 1    vj.sub.-- comp.setXPt(0,getXPt(0)+40);    vj.sub.-- comp.setYPt(0,getYPt(0)+40);    vj.sub.-- comp.setXPt(1,getXPt(1)+40);    vj.sub.-- comp.setYPt(1,getYPt(1)+40);    vj.sub.-- comp.setXPt(2,getXPt(2)+40);    vj.sub.-- comp.setYPt(2,getYPt(2)+40);    vj.sub.-- comp.setImages(normalImage, selectedImage); // Pass references    to the static images down to the node    vj.sub.-- comp.nodeRect = new Rectangle(i-3,j-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);    vj.sub.-- comp.setSelected(true);    vj.theDocument.add(vj.sub.-- comp.comp);    vj.sub.-- comp.comp.validate( );    vj.sub.-- comp.comp.reshape(comp.bounds( ).x+50,comp.bounds(    ).y+50,comp.    bounds( ).width,comp.bounds( ).height+1);    vj.sub.-- comp.comp.show( );    return vj.sub.-- comp;     } catch(Exception e) {      System.out.println(e);      return null;     }    }    public static void getImages(GIFFactoryf){    normalImage = f.GetGIF(out);    selectedImage = f.GetGIF(in);    }    // Component Initialization    public void VJVScrollbarInit(intx.sub.-- pt, int y.sub.-- pt) {     try {    String theText = new String("VScrollbar    "+String.valueOf(instanceCount++));    setNormalIcon(out);    setSelectedIcon(in);    bar = new AWTVScrollbar(this);    setName(theText);    setComponent((Component)bar);    setComponentURL(url.sub.-- name);    setComponentInfo(info.sub.-- name);    VJNodeInit(false,x.sub.-- pt,y.sub.-- pt,true);    addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOutput,VJPort.Nort    hLeftCenter); // Pin0    addPort(port1.sub.-- info,port 1.sub.-- name,VJPort.InputOutput,VJPort.Nor    thRightCenter); // Pin 1    addPort(port2.sub.-- info,port2.sub.-- name,VJPort.InputOutput,VJPort.Sout    hCenter); // Pin 1    setImages(normalImage,selectedImage); //Pass references to the    static images down to the node    nodeRect = new Rectangle(x.sub.-- pt-3,y.sub.-- pt-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);     } catch(Exception e) {    System.out.println(e);     }    }    public void request(int port,int time) { }    public int componentID( ) {return 3;}    public void disconnecting(int port) {    switch(port){    case 0: request.sub.-- index0= -1; send.sub.-- index0 = -1    break;    case 1: request.sub.-- index1 = -1; send.sub.-- index1 = -1;    break;    case 2: request.sub.-- index2 = -1; send.sub.-- index2 = -1;    break;    }    }    public void connecting(int port) {    switch(port){    case 0: request.sub.-- index0=0; send.sub.-- index0 = 0;    vj.request(0,request.sub.-- index0++,this);    break;    case 1: request.sub.-- index1=0; send.sub.-- index1 = 0;    vj.request(1,request.sub.-- index1++,this);    break;    case 2: request.sub.-- index1=0; send.sub.-- index2 = 0;    vj.request(2,request.sub.-- index2++,this);    break;     }    }    public void load(String s) {    StringTokenizer tokenStream = new StringTokenizer(s);    int max =    Integer.valueOf(tokenStream.nextToken( )).intValue( );    int min =    Integer.valueOf(tokenStream.nextToken( )).intValue( );    int value =    Integer.valueOf(tokenStream.nextToken( )).intValue( );    int visible =    Integer.valueOf(tokenStream.nextToken( )).intValue( );    bar.setValues(value,visible,min,max);    }    public String save( ) {    int max = bar.getMaximum( );    int min = bar.getMinimum( );    int value = bar.getValue( );    int visible = bar.getVisible( );    return max+" "+min+" "+value+" "+visible;}    public void set(Object o,int port,int time) {    int max,min,cur;    boolean ok = false;    max = bar.getMaximum( );    min = bar.getMinimum( );    cur = bar.getValue( );    switch(port){    case0:    if(time==0){           if(o instanceofString)            {min = Integer.valueOf((String)o).intValue( );    ok=true;}           if(o instanceofInteger) {min=((Integer)o).intValue( );    ok=true;}           if(o instanceofDouble) {min=((Double)o).intValue( );    ok=true;}           if(o instanceofLong) {min=((Long)o).intValue( );ok=true;    }           if(o instanceofFloat) {min=((Float)o).intValue( );    ok=true;}    }    break;    case 1:    if(time==0){           if(o instanceofString)            {max = Integer.valueOf((String)o).intValue( );    ok=true;;}           if(o instanceofInteger) {max=((Integer)o).intValue( );    ok=true;}           if(o instanceofDouble) {max=((Double)o).intValue( );    ok=true;}           if(o instanceofLong) {max=((Long)o).intValue( ) ; ok=true;    }           if(o instanceofFloat) {max=((Float)o).intValue( ) ; ok=true;    }           }           break;    default:           if(o instanceofString)            {cur = Integer.valueOf((String)o).intValue( );ok=true;}           if(o instanceofInteger) {cur=((Integer)o).intValue( );    ok=true;}           if(o instanceofDouble) {cur=((Double)o).intValue( );    ok=true;}           if(o instanceofLong) {cur=((Long)o).intValue( );ok=true;}           if(o instanceofFloat) {cur=((Float)o).intValue( ); ok=true;}           if(ok) vj.request(2,request.sub.-- index2++,this);           break;    }    ok=false;    bar.setValues(cur,bar.getVisible( ),min,max);    }    public boolean handleEvent(Evente) {    if(send.sub.-- index2>=0&&e.id<606&&e.id>600)vj.set((Object)(new    Integer(bar.getValue( ))),2,send.sub.-- index2++,this);    return false;    }    public void propertiesEditor( ) {     if(edit==null){    edit = new vscrollbarEditor((Frame)(vj.theFrame),this);    edit.pack( );    edit.resize(10*32,5*32);    edit.show( );     }    }    public void init( ){ };    public void start( ){ };    public void stop( ){ };    public void destroy( ){ };    public void reset( ){     request.sub.-- index0=0; vj.request(0,request.sub.-- index0++,this);    };    } // end class    class vscrollbarEditor extends Frame    {    VJVScrollbar vjsb;    TextField max;    TextField min;    TextField visible;    TextField current;    Button ok;    Button cancel;    boolean dirty = false;    public vscrollbarEditor(Frame parent,VJVScrollbar c)    {    super("Vertical Scrollbar Editor");    setBackground(Color.lightGray);    setLayout(new BorderLayout( ));     Panel p = new Panel( );     vjsb = c;     // p.setLayout(new BorderLayout( ));    Panel centerPanel = new Panel( );    p.add(new Button("OK"));    p.add(new Button("Cancel"));    add("South",p);    dirty = false;    centerPanel.setLayout(newGridLayout(2,4));    centerPanel.add(new Label("Current"));    centerPanel.add(new Label("Visible"));    centerPanel.add(new Label("Maximum"));    centerPanel.add(new Label("Minimum"));    current = new TextField(String.valueOf(vjsb.bar.getValue( )));    visible = new TextField(String.valueOf(vjsb.bar.getVisible( )));    max = new TextField(String.valueOf(vjsb.bar.getMaximum( )));    min = new TextField(String.valueOf(vjsb.bar.getMinimum( )));    centerPanel.add(current);    centerPanel.add(visible);    centerPanel.add(max);    centerPanel.add(min);    add("Center",centerPanel);     }     public boolean handleEvent(Event evt)     {    switch(evt.id) {           case Event.ACTION.sub.-- EVENT:           {             if("OK".equals(evt.arg))             { vjsb.edit= null;    vjsb.bar.setValues(Integer.valueOf(current.getText( )).intValue( ),    Integer.valueOf(visible.getText( )).intValue( ),              Integer.valueOf(min.getText( )).intValue( ),              Integer.valueOf(max.getText( )).intValue( ));           dispose( );           return true;             }    if("Cancel".equals(evt.arg))    { vjsb.edit = null;    dispose( );    return true;    }    returnfalse;    }    default:            return false;    }    }    }    __________________________________________________________________________

FIG. 9 depicts an example of a VJScrollbar object 604b in the logicalview 500. The physical view 402 illustrates a simple AWT horizontalscrollbar 902 having diamond shaped I/O pins or ports 904. The diamondshape indicates that the I/O pin is bi-directional or two way inoperational nature; that is, they accept inputs or transmit outputs, asthey are utilized. The I/O pins can be shaped like a triangle, ratherthan a diamond. If they are diamond shaped, then those I/O pins willhandle an output or an input depending on the direction in which theypoint. I/O pins 904, which are sometimes referred to as "net pins", canbe coded as follows:

    ______________________________________    import java.awt.*;    public class VJNetPin extends VJNode {    // Attributes of this component    static int instanceCount = 0;    static Image normalImage;    static Image selectedImage;    final static String out   = "out.sub.-- np.gif";    final static String in   = "in.sub.-- np.gif";    final static String port0.sub.-- info = "input or output and object";    final static String port0.sub.-- name = "Pin 0";    final static String url.sub.-- name = "netpin.html";    final static String info.sub.-- name = "Connects components inside a    container to a pin of the container";    VJ vj;    netpinEditor edit=null;    VJContainer theContainer;    boolean connected = false;    boolean requested = false;    int theLocation;    int requestTime = 0;    int theConnection = -1;    // Constructor    public VJNetPin(VJ v){     super(v);     vj = v;    VJNode dup( ) {     return null;    }    public static void getImages(GIFFactory f) {     normalImage = f.GetGIF(out);     selectedImage = f.GetGIF(in);    }    public void setContainer(VJContainerc) {     theContainer = c;    }    public void setConnection(int c) {     theConnection = c;    }    // Component Initialization    public void VJNetPinInit(intx.sub.-- pt, int y.sub.-- pt) {     try {    setNormalIcon(out);    setSelectedIcon(in);    setName("VJNetPin");    setComponent(null);    setComponentURL(url.sub.-- name);    setComponentInfo(info.sub.-- name);    VJNodeInit(false,x.sub.-- pt,y.sub.-- pt,false);    addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOutput,    VJPort.SouthCenter); // Pin0    setImages(normalImage,selectedImage); // Pass references to the    static images down to the node    nodeRect = new Rectangle(x.sub.-- pt-3,y.sub.-- pt-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);     } catch(Exception e) {     System.out.println(e);     }    }    public int componentID( ) {return 6;}    public void disconnecting(int port) {    connected = false;    }    public void connecting(int port) {     connected = true;     if(requested) {    vj.request(0,requestTime,this);    requested = false;     }    }    public void load(String s) {    }    public String save( ) {    return " ";}    public void reset( ) { }    public void request(int port,int time) {    // what if theConnection <0?    theContainer.requestOUT(theConnection,time);    }    public void requestIN(int time) {     if(connected) vj.request(0,time,this);     else {requestTime = time; requested = true;}    }    public void set(Object o,int port,int time) {     if(theConnection>=0)    theContainer.setOUT(o,theConnection,time);     // vj.request(0,request.sub.-- index0++,this);    }    public void setIN(Object o,int time) {    vj.set(o,0,time,this);    }    public void propertiesEditor( ) {    if(edit==null){    edit = new netpinEditor((Frame)(vj.theFrame),this);    edit.pack( );    edit.show( );    }    }    public void init( ){ };    public void start( ){ };    public void stop( ){ };    public void destroy( ){ };    }    class netpinEditor extends Frame    {    VJNetPin vjc;    TextField tf;    Button b;    Button cancel;    public netpinEditor(Frame parent,VJNetPin c)    {     super("Pin Editor");    setLayout(new BorderLayout( ));    add("North",new Label("Select a pin"));    vjc = c;    tf = new TextField(new Integer(vjc.theLocation).toString( ));    add("Center",tf);    b = new Button("OK");    cancel = new Button("Cancel");    Panel sp = new Panel( );    sp.add(b);     sp.add(cancel);     add("South",sp);    }    public boolean handleEvent(Event evt)    { // System.out.println(evt.toString( ));    switch(evt.id){           case Event.ACTION.sub.-- EVENT:           {             if("OK".equals(evt.arg))             {           vjc.theLocation =    (Integer.valueOf(tf.getText( ))).intValue( );           // vjc.theContainer.addNewPort(vjc,"fred","jim");           vjc.edit = null;                dispose( );                return true;             }    if("Cancel".equals(evt.arg))    { vjc.edit = null;           dispose( );           return true;    }    return false;           }           default:             return false;    }    }    }    ______________________________________

FIG. 10 shows the two pin capability of scrollbar 604b. Note that eachof the pins 902 and 904 are diamond shaped or two way ports. If a valueif placed on these ports, it sets the scrollbar to that level.Conversely, if a value is taken from one of these ports, it reflects theposition of scrollbar 604b.

In practice, the two way or bidirectional ports are first initialized totheir two way state. The ports can then function either as an input portor as an output port depending solely on the way they are used. Eachbidirectional port is provided with bidirectional capability by having asend message method defined for all outgoing transactions and a receivemessage method defined for all incoming transactions in the componentfor each bidirectional port. Thus, the method corresponding to thedirection is invoked based on the flow of the message through the port.

For example, if inputs are connected to the two-way ports 904a or 904bin FIG. 10, they would function as input ports. Two-way port 906 wouldthen function as the output port since it is the only port left thatcould serve in that role. In the preferred arrangement, components setthemselves internally to reflect the status of each of theirbidirectional ports, in accordance with the way they are being used. Thebidirectional ports permit greater connective flexibility and savescreen real estate as well.

When a connection to another component is completed, the connectingcomponent sends a message to the component at the other end of theconnection indicating how its connecting port is set, input or output.The message receiving component then makes sure that its connectionparticipating port is set accordingly. If the message receivingcomponent's port is bidirectional, the port is set opposite to thestatus of the first connected port. If the message receiving component'sconnecting port is bidirectional, that port is set opposite to thestatus of the first connected port. If the message receiving component'sport is unidirectional and as such is in conflict with the status of thefirst connected port, that is, it is set to "output" when the firstconnected port is also set to "output", the connection is prohibited andan appropriate error message is displayed.

FIG. 11 illustrates the addition of a second vertical scrollbar thatwill be set to track the range of the Fahrenheit temperature scale. Notethat the vertical scrollbar editor 1104 has been adjusted to setscrollbar 1102 to a maximum value of 212 (boiling point) and a minimumvalue of 32 (freezing point). Prior to being adjusted, scrollbar 1102has a current value of 71 with only 10 units of its total range actuallyvisible.

Dynamic editing is accomplished by providing each component that wouldhave need of an editor with that capability as an integral part of theclass template from which it is instantiated. Each customizer window oreditor is defined in predetermined class templates as a methodcorresponding to the customizer method.

Thus, when such edit capable components are instantiated in either thelogical view 402 or the physical view 500, their built-in customizer oredit widow 1104 is invoked, see FIG. 11, and opens automatically. Theeditor appears in the view ready for use to change or customize theproperties of the component, in this case scrollbar 604b, based on userinteraction with the customizer or editing window 1104.

As shown in the flowchart of FIG. 11A, editor capability is added atblock 1120 to each class template for which an editing capability isdesired in component objects instantiated therefrom. An editing window,as indicated by block 1122 is defined as a method corresponding to theeditor. The properties and their limits are also defined for eachcomponent editor as shown by block 1124. An editing window is opened byblock 1126 when the component with which it is associated is dragged anddropped or instantiated for use.

After the user finishes editing the component's properties and clicks"OK", the editing window is closed and the property changes are acceptedand displayed immediately in the appropriate view by block 1128. Afterproperty editing is completed, the editable components are monitored fora user action (usually a mouse click) which indicates that propertyre-editing is desired for a specific component, as per block 1130. Whenthat occurs, block 1132 opens the editor widow 1104 again to permitcomponent property changes to be made. Thereafter, control is returnedto block 1128 and the user re-editing changes are accepted. Finally,monitoring of the editable components resumes as per block 1130.

It is important to note that the user is not required to take any actionto invoke an editor or be concerned about the suitability orappropriateness of the editor with respect to the component beingcustomized. Moreover, the editor is customized for the specificcomponent with which it is associated. If an editor appears when acomponent is instantiated, then the user instantaneously knows that thatparticular component is customizable. In addition, the user sees andknows just which properties of the component are editable and to whatlimits. Further, the user can make any desired customizing changeswithout having to write any code to implement those changes. Other usesof a component editor are shown in FIGS. 12 and 15.

FIG. 12 shows how VJ Tool is utilized to add text to scrollbars 604b and1102 so that the function they perform or represent can be labeled andthereby identified to any user. First, the simple text field component506 is invoked by clicking on its icon and dragging it onto the physicalview 500. The text field representation 1202 can then be dropped at anydesired location and, as desired, sized to match the element it willidentify, in this case scrollbar 604b. The text field or label editor1204 is then used to generate the actual text or scrollbar label.

The label text field component is coded as follows:

    ______________________________________    import java.awt.*;    import java.util.*;    public class VJLabel extends VJNode {    // Attributes of this component    public AWTLabe1 label;    static int instanceCount = 0;    labelEditor edit;    static Image normalImage;    static Image selectedImage;    final static String out = "out.sub.-- la.gif";    final static String in = "in.sub.-- la.gif";    final static String port0.sub.-- info = "for setting the text";    final static String port0.sub.-- name = "Pin 0";    final static String url.sub.-- name = "label.html";    final static String info.sub.-- name = "A simple AWT label";    VJ vj;    int send.sub.-- index=0;    int request0.sub.-- index=0;    // Constructor    public VJLabel(VJ v){     super(v);     vj = v;    VJNode dup( ) {     VJLabel vj.sub.-- comp = new VJLabel(vj);     try{    int i = x+40;    int j = y+40;    AWTLabel 1 = new AWTLabel(label.getText( ),vj.sub.-- comp);    vj.sub.-- comp.label = .sub.-- 1;    vj.sub.-- comp.setNormalIcon(out);    vj.sub.-- comp.setSelectedIcon(in);    vj.sub.-- comp.setName(label.getText( ));    vj.sub.-- comp.setComponent((Component)1);    vj.sub.-- comp.setComponentURL(url.sub.-- name);    vj.sub.-- comp.set.ComponentInfo(info.sub.-- name);    vj.sub.-- comp.VjNodeInit(false,i,j,true);    vj.sub.-- comp.addPort(port0.sub.-- info,port0.sub.-- name,VJPort.Input,    VJPort.NorthCenter); // Pin 0    vj.sub.-- comp.setXPt(0,getXPt(0)+40);    vj.sub.-- comp.setYPt(0,getYPt(0)+40);    vj.sub.-- comp.setImages(normalImage,selectedImage); // Pass references    to the static images down to the node    vj.sub.-- comp.nodeRect = new Rectangle(i-3,j-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);    vj.sub.-- comp.setSelected(true);    vj.theDocument.add(vj.sub.-- comp.comp);    vj.sub.-- comp.comp.validate( );    vj.sub.-- comp.comp.reshape(comp.bounds( ).x+50,comp.bounds( ).y+50,    comp.bounds( ).width,comp.bounds( ).height);    vj.sub.-- comp.comp.show( );    return vj.sub.-- comp;     } catch(Exception e) {      System.out.println(e);      return null;     }    }    public static void getImages(GIFFactory f){    normalImage = f.GetGIF(out);    selectedImage = f.GetGIF(in);    }    // Component Initialization    public void VJLabelInit(int x.sub.-- pt, int y.sub.-- pt) {     try{    String theText = new String("Label    "+String.valueOf(instanceCount++));    label = new AWTLabel(theText,this);    label.setFont(new Font("Courier", Font.PLAIN, 14));    setNormalIcon(out);    setSelectedIcon(in);    setName(theText);    setComponent((Component)label);    setComponentURL(url.sub.-- name);    setComponentInfo(info.sub.-- name);    VJNodeInit(false,x.sub.-- pt,y.sub.-- pt,true);    addPort(port0info,port0.sub.-- name,VJPort.Input,VJPort.NorthCenter);    // Pin 0    setImages(normalImage,selectedImage); //Pass references to the    static images down to the node    nodeRect = new Rectangle(x.sub.-- pt-3,y.sub.-- pt-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);     } catch(Exception e) {    System.out.println(e);     }    }    public void request(int port,int time) { }    public int componentID( ) {return 2;}    public void load(String s) {    }    public String save( ) {    return " ";}    public void disconnecting(int port) {    switch(port){    case 0: request0.sub.-- index= -1;    break;    }    }    public void connecting(int port) {    switch(port){    case 0: request0.sub.-- index=0;    vj.request(0,request0.sub.-- index++,this);    break;    }    }    public void set(Object o,int port,int time) {    boolean ok = false;    if(o instanceof Color) {label.setForeground((Color)o); ok=true;}    if(o instanceof String) {label.setText((String)o); ok = true;}    if(o instanceof Long) {    label.setText((String)(((Long)o).toString( ))); ok = true;}    label.if(o instanceof Double) {    setText((String)(((Double)o).toString( ))); ok = true;}    if(o instanceof Float) {    label.setText((String)(((Float)o).toString( ))); ok = true;}    if(o instanceof Integer) {    label.setText((String)(((Integer)o).toString( ))); ok = true;}    if(o instanceof Boolean) {    label.setText((String)(((Boolean)o).toString( ))); ok = true;}    if(ok) {    // System.out.println(name + "has input at "+    String.valueOf(time)+ "= "+ getText( ));    if(time <199) vj.request(0,request0.sub.-- index++,this);    }    ok = false;    }     public boolean handleEvent(Event e) {    return false;    }    public void propertiesEditor( ) {     if(edit==null){    edit = new labelEditor((Frame)(vj.theFrame),this);    edit.pack( );    //edit.resize(12*32,6*32);    edit.show( );     }    }    public void init( ){ };    public void start( ){ };    public void stop( ){ };    public void destroy( ){ };    } // end class VJLabel    class labelEditor extends Frame    {    VJLabel vjl;    TextField tf;    Button ok;    Button cancel;    boolean dirty;    public labelEditor (Frame parent,VJLabel 1)    {     super("Label Editor");    setLayout(new BorderLayout( ));    vjl = 1;    tf = new TextField(vjl.label.getText( ));    add ("Center",tf);    ok = new Button("OK");    cancel = new Button("Cancel");    Panel sp = new Panel( );    sp.add(ok);     sp.add(cancel);     add("South",sp);    }    public boolean handleEvent(Event evt)    { // System.out.println(evt.toString( ));    switch(evt.id){           case Event.ACTION.sub.-- EVENT:           {             if("OK".equals(evt.arg))             {           vjl.label.setText(tf.getText( ));           vjl.edit = null;               dispose( );               return true;             }    if("Cancel".equals(evt.arg))    { vjl.edit = null;           dispose( );           return true;    }    return false;           }           default:             return false;    }    }    }    ______________________________________

As shown in FIG. 13, text field 1202 has been made into the "CENTIGRADE"label 1202a above scrollbar 604b through use of the text field editor1204. Label "FAHRENHEIT" 1302 has been generated in the same manner andpositioned above scrollbar 1102 (not shown in FIG. 13).

It should be noted that several of the components described herein,vertical scrollbars 604a and 604b and text field 1202 label editor, areprovided with their own editors, vertical scrollbar editor 604 and labeleditor 1204, which permits the predefined properties of the associatedcomponents to be directly and dynamically edited. Such editing takesplace without the user having to exit VJ Tool or having to write anycode to support the desired editorial changes.

FIG. 13 also illustrates in logical view 402, representations ofscrollbars, text and bicopy objects that will be used to functionallylink scrollbars 604b and 1102. Objects 1306 and 1312 logically representscroll bars 604b and 1102 while label objects 1304 and 1310 representthe labels 1202a and 1302 respectively. Bicopy is a backend componentthat is only found in the logical view palette. A bicopy object, such as1308 and 1314, as implemented in accordance with a preferred embodimentof the present invention, will place whatever is input on one of itsdiamond shaped I/O pins 1308a, 1308b, 1308c or 1398d on the other I/Opins.

Bicopy, which functions like a multiplexor, is coded as follows:

    ______________________________________    import java.awt.*;    import java.util.*;    public class VJBiCopy extends VJNode {    // Attributes of this component    static int instanceCount = 0;    static Image normalImage;    static Image selectedImage;    final static String out.sub.-- bi  = "out.sub.-- bi.gif";    final static String in.sub.-- bi  = "in.sub.-- bi.gif";    final static String port0.sub.-- info = "Pin 0";    final static String port0.sub.-- name = "Pin 0";    final static String port1.sub.-- info = "Pin 1";    final static String port1.sub.-- name = "Pin 1";    final static String port2.sub.-- info = "Pin 2";    final static String port2.sub.-- name = "Pin 2";    final static String port3.sub.-- info = "Pin 3";    final static String port3.sub.-- name = "Pin 3";    final static String url.sub.-- name = "bicopy.html";    final static String info.sub.-- name = "Whatever is input on one pin is    output    on the others";    VJ vj;    int send.sub.-- index0 = -1;    int send.sub.-- index1 = -1;    int send.sub.-- index2 = -1;    int send.sub.-- index3 = -1;    int request.sub.-- index0 = -1;    int request.sub.-- index1 = -1;    int request.sub.-- index2 = -1;    int request.sub.-- index3 = -1;    // Constructor    public VJBiCopy(VJ v){     super(v);     vj = v;    VJNode dup( ) {     VJBiCopy b = new VJBiCopy(vj);     try {    int i = x+40;    int j = y+40;    b.setNormalIcon(out.sub.-- bi);    b.setSelectedIcon(in.sub.-- bi);    b.setName("BiCopy");    b.setComponent(null);    b.setComponentURL(url.sub.-- name);    b.setComponentInfo(info.sub.-- name);    b.VJNodeInit(false,i,j,false);    b.addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOutput,    VJPort.NorthCenter); // Pin 0    b.addport(port1.sub.-- info,port1.sub.-- name,VJPort.InputOutput,    VJPort.EastCenter); // Pin 1    b.addPort(port2.sub.-- info,port2.sub.-- name,VJPort.InputOutput,    VJPort.SouthCenter); // Pin 2    b.addPort(port3.sub.-- info,port3.sub.-- name,VJPort.InputOutput,    VJPort.WestCenter); // Pin 3    b.setXPt(0,getXPt(0)+40);    b.setYpt(0,getYPt(0)+40);    b.setXPt(1,getXPt(1)+40);    b.setYPt(1,getYPt(1)+40);    b.setXPt(2,getXPt(2)+40);    b.setYPt(2,getYPt(2)+40);    b.setXPt(3,getXPt(3)+40);    b.setYPt(3,getYPt(3)+40);    b.setImages(normalImage,selectedImage); // Pass references to the    static images down to the node    b.nodeRect = new Rectangle(i-3,j-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp w)+3);    b.setSelected(true);    return b;     } catch(Exception e) {      System.out.println(e);      return null;     }    }    public static void getImages(GIFFactory f){    normalImage = f.GetGIF(out.sub.-- bi);    selectedImage = f.GetGIF(in.sub.-- bi);    }    // Component Initialization    public void.VJBiCopyInit(intx.sub.-- pt, int y.sub.-- pt) {     try{    setNormalIcon(out.sub.-- bi);    setSelectedIcon(in.sub.-- bi);    setName("bicopy");    setComponent(null);    setComponentURL(url.sub.-- name);    setComponentInfo(info.sub.-- name);    VJNodeInit(false,x.sub.-- pt,y.sub.-- pt,false);    addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOutput,    VJPort.NorthCenter); // Pin 0    addPort(port1.sub.-- info,port1.sub.-- name,VJPort.InputOutput,    VJPort.EastCenter); // Pin 1    addPort(port2.sub.-- info,port2.sub.-- name,VJPort.InputOutput,    VJPort.SouthCenter); // Pin 2    addPort(port3.sub.-- info,port3.sub.-- name,VJPort.InputOutput,    VJPort.WestCenter); // Pin 3    setImages(normalImage,selectedImage); // Pass references to the    static images down to the node    nodeRect = new Rectangle(x.sub.-- pt-3,y.sub.-- pt-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedlmage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);     } catch(Exception e) {     System.out.println(e);     }    }    public void request(int port,int time) { }    public int componentID( ) {return 5;}    public void disconnecting(int port) {    switch(port) {    case 0: send.sub.-- index0 = -1; request.sub.-- index0 = -1;           break;    case 1: send.sub.-- index1 = -1; request.sub.-- index1 = -1;           break;    case 2: send.sub.-- index2 = -1; request.sub.-- index2 = -1;           break;    case 3: send.sub.-- index3 = -1; request.sub.-- index3 = -1;           break;    }    }    public void connecting(int port) {           switch(port){           case 0: request.sub.-- index0=0; send.sub.-- index0 = 0;                  vj.request(0,request index0++,this);                  break;    case 1: request.sub.-- index1=0;send.sub.-- index1 = 0;    vj.request(1,request.sub.-- index1++,this);    break;    case 2: request.sub.-- index2=0;send.sub.-- index2 = 0;    vj.request(2,request.sub.-- index2++,this);    break;    case 3: request.sub.-- index3=0;send.sub.-- index3 = 0;    vj.request(3,request.sub.-- index3++,this);    break;    }    }    public void load(String s) {    }    public String save( ) {    return " ";}    public void set(Object o,int port,int time){    switch(port){    case 0: if (request.sub.-- index1 > 0) vj.set(o,1,send.sub.-- index1++,thi    s);    if (request.sub.-- index2 > 0) vj.set(o,2,send.sub.-- index2++,this);    if (request.sub.-- index3 > 0) vj.set(o,3,send.sub.-- index3++,this);    vj.request(0,request.sub.-- index0++,this);    break;    case 1: if (request.sub.-- index0 > 0) vj.set(o,0,send.sub.-- index0++,thi    s);    if (request.sub.-- index2 > 0) vj.set(o,2,send.sub.-- index2++,this);    if (request.sub.-- index3 > 0) vj.set(o,3,send.sub.-- index3++,this);    vj.request(1,request.sub.-- index1 ++,this);    break;    case 2: if (request.sub.-- index1 > 0) vj.set(o,1,send.sub.-- index1++,thi    s);    if (request.sub.-- index0 > 0) vj.set(o,0,send.sub.-- index0++,this);    if (request.sub.-- index3 > 0) vj.set(o,3,send.sub.` index3++,this);    vj.request(2,request.sub.-- index2++,this);    break;    case 3: if (request.sub.-- index1 > 0) vj.set(o,1,send.sub.-- index1++,thi    s);    if (request.sub.-- index2 > 0) vj.set(o,2,send.sub.-- index2++,this);    if (request.sub.-- index0 > 0) vj.set(o,0,send.sub.-- index0++,this);    vj.request(3,request.sub.-- index3++,this);    break;    }    }    public void propertiesEditor( ) {    }    public void init( ){ };    public void start( ){ };    public void stop( ){ };    public void destroy( ){ };    } // end class VJButton    ______________________________________

FIG. 13A illustrates a flowchart of the process by which the bicopycomponent 1308 shown in FIG. 13 functions. The act of dragging anddropping a new bicopy component onto the logical desktop 402 or ofdropping an assembly from folder 542, which assembly contains a bicopycomponent, onto the logical view desktop 402 actually starts the bicopycomponent as called for in block 1330. A test is next made to see thereis a saved, prior state for bicopy element 1308 that needs to berestored by decsion block 1332. If restoration is neded, control ispassed to block 1334 which obtains the necessary values and has theports set accordingly in block 1344.

If the bicopy component is new, its two-way ports are initialized or setto zero in bock 1336. Once that has been done, the ports are polled inblock 1338 to monitor connection attempts. Decision block 1340 returnscontrol to block 1338 for continued polling if there were no connectionsmade to any of bicopy's component ports. If a proper connection has beenmade, a connection sufficient to place a value on one of the bicopycomponet's ports, control is passed to block 1342 where the type andvalue of the connection is identified.

Thus, if a connection has been made from a text field, a characterstring is placed on one of the bicopy component's ports and captured bythe Bicopy component. Similarly, if an integer value, such as 32,isplaced placed on one of the bicopy component's ports, that type andvalue is also recognized and captured. Once the type and value of aninput are known, the remaining ports are set to provide the same typeand value as the input by block 1344. Thus, at this point, see FIG. 16,bicopy component 1308 would have its port 1308c set by the output ofscrollbar representation 1306 to the current value (position) of thescrollbar. This means that ports 1308a, 1308b and 1308d, which act asoutput ports, will carry the output value of scrollbar 1306 until theinput connection to port 1308c is changed.

Decision block 1346, which is advised of the initial connection by block1342, checks for removal of the input value to bicopy component 1308 andreturns control back to block 1344 if it has not been removed or toblock 1336 for reinitialization if it has been removed.

FIG. 14 shows addition of splitters 1402 and 1404 in the logical view402. Splitter objects 1402 and 1404 are used to connect I/O pins tocomponents that are functionally involved in a defined relationshipappearing in the logical view 402. Splitters are instantiated form thesplitter palette component 558 of logical view 402 and are dragged anddropped to a suitable location on the logical view desktop. Splitterobjects are formed pursuant to their implementing code (VJSplit) asfollows:

    ______________________________________    import java.awt.*;    import java.util.*;    public class VJSplit extends VJNode {    // Attributes of this component    static int instanceCount = 0;    static Image normalImage;    static Image selectedImage;    final static String out   = "OSplit.gif";    final static String in   = "ISplit.gif";    final static String port0.sub.-- info = "An input/output pin";    final static String port0.sub.-- name = "Pin 0";    final static String port1.sub.-- info = "An output pin";    final static String port1.sub.-- name = "Pin 1";    final static String port2.sub.-- info = "An input pin";    final static String port2.sub.-- name = "Pin 2";    final static String url.sub.-- name = "split.html";    final static String info.sub.-- name = "A Splitter used to connect    input/output pins to componets that are either input or output";    VJ vj;    int send.sub.-- index2 = 0;    int request.sub.-- index0 = 0;    int request.sub.-- index1 = 0;    // Constructor    public VJSplit(VJ v){     super(v);     vj = v;    VJNode dup( ) {     VJSplit b = new VJSplit(vj);     try{    int i = x+40;    int j = y+40;    b.setNormalIcon(out);    b.setSelectedIcon(in);    b.setName("Splitter");    b.setComponent(null);    b.setComponentURL(url.sub.-- name);    b.setComponentInfo(info.sub.-- name);    b.VJNodeInit(false,i,j,false);    b.addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOutput,    VJPort.NorthCenter); // Pin 0    b.addPort(port1.sub.-- info,port1.sub.-- name,VJPort.Output,    VJPort.SouthLeftCenter); // Pin 0    b.addPort(port2.sub.-- info,port2.sub.-- name,VJPort.Input,VJPort.SouthRig    htCente    r); // Pin 0    b.setXPt(0,getXPt(0)+40);    b.setYPt(0,getYPt(0)+40);    b.setXPt(1,getXPt(1)+40);    b.setYPt(1,getYPt(1)+40);    b.setXPt(2,getXPt(2)+40);    b.setYPt(2,getYPt(2)+40);    b.setImages(normalImage,selectedImage); // Pass references to the    static images down to the node    b.nodeRect = new Rectangle(i-3,j-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp w)+3);    b.setSelected (true);    return b;     } catch(Exception e) {     System.out.println(e);     return null;     }    }    public static void getImages(GIFFactoryf){    normalImage = f.GetGIF(out);    selectedImage = f.GetGIF(in);    }    // Component Initialization    public void VJSplitInit(int /x.sub.-- pt, int y.sub.-- pt) {     try {    setNormalIcon(out);    setSelectedIcon(in);    setName("Splitter");    setComponent(null);    setComponentURL(url.sub.-- name);    setComponentInfo(info.sub.-- name);    VJNodeInit(false,x.sub.-- pt,y.sub.-- pt,false);    addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOutput,    VJPort.NorthCenter); // Pin 0    addPort(port1.sub.-- info,port1.sub.-- name,VJPort.Output,VJPort.SouthLeft    Center);    // Pin 0    addPort(port2.sub.-- info,port2.sub.-- name,VJPort.Input,VJPort.SouthRight    Center);    // Pin 0    setImages(normalImage, selectedImage); // Pass references to the    static images down to the node    nodeRect = new Rectangle(x.sub.-- pt-3,y.sub.-- pt-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);     } catch(Exception e) {     System.out.println(e);     }    }    public int componentID( ) {return 12;}    public void disconnecting(int port) { }    public void connecting(int port) { }    public void load(String s) {    }    public String save( ) {    return " ";}    public void propertiesEditor( ) { }    public void reset( ) { }    public void request(int port,int time) {    switch(port){    case 0: vj.request(2,time,this);           break;    case 1: vj.request(0,time,this);           break;    }    }    public void set(Object o,int port,int time) {    switch(port){    case 0: vj.set(o,1,time,this);           break;    case 2: vj.set(o,0,time,this);           break;    }    }    public void init( ){ };    public void start( ){    };    public void stop( ){    };    public void destroy( ){ };    }    ______________________________________

FIG. 15 shows the addition of a calculator object 1502. Calculatorobject 1502 is instantiated from calculator component 572 of the logicalview palette when the mouse is clicked over the calculator icon and theresulting image is dragged into the logical view window. When calculatorobject 1502 is created, evaluator editor 1504 is popped up so thatexpressions to be evaluated by the calculator can be input thereto. Inthis particular example, the Fahrenheit to Centigrade conversionexpression to be evaluated is entered and the calculator is therebyinformed what its computational task will be.

FIG. 16 illustrates the interconnections of several objects to achievethe appropriate Centigrade/Fahrenheit relationship between scroll bars604b and 1102. Building on to the arrangement depicted in FIG. 15, theuser would add two simple text field objects 1602 and 1603 in physicalview 500 by clicking on the simple text field icon 506 twice and thendragging and dropping each resultant text field object 1602 and 1603 sothat each is located below and adjacent to the scrollbar it containsinformation for.

When the text field objects are created, logical representationsthereof, 1604 and 1606 respectively, are created by VJ Tool in thelogical window. The appropriate interconnections between and amongst theseveral objects in the logical view 402 are then made and the resultsdisplayed in the text fields 1602 and 1604 as a direct function of wherethe scrollbars are actually located. Since scrollbar 604b is at itsminimum position, which is zero, text field 1602 accurately displaysthat result. The display of the position results in a text field withoutthe intervening need to write additional code to transform the scrollbaroutput, an integer or floating point value to an ASCII string. VJ Tooltakes care of that task for the user and permits concentration on theproblem being solved.

VJTextField is coded as follows:

    ______________________________________    import java.awt.*;    import java.util.*;    public class VJTextField extends VJNode {    // Attributes of this component    public AWTTextField text;    static int instanceCount = 0;    textfieldEditor edit;    static Image normalImage;    static Image selectedImage;    final static String out = "out.sub.-- te.gif";    final static String in = "in.sub.-- te.gif";    final static String port0.sub.-- info = "for getting or seeting the    current text";    final static String port0.sub.-- name = "Pin 0";    final static String url.sub.-- name = "textfield.html";    final static String info.sub.-- name = "A simple AWT textfield";    VJ vj;    int send.sub.-- index = -1;    int request.sub.-- index = 0;    int c.sub.-- width,c.sub.-- height;    // Constructor    public VJTextField(VJ v){     super(v);     vj = v;    VJNode dup( ) {     VJTextField vj.sub.-- comp = new VJTextField(vj);     try {    int i = x+40;    int j = y+40;    AWTTextField t = new AWTTextField(text.getText( ),vj.sub.-- comp);    vj.sub.-- comp.text = t;    t.setFont(text.getFont( ));    vj.sub.-- comp.setNormalIcon(out);    vj.sub.-- comp.setSelectedIcon(in);    vj.sub.-- comp.setName(text.getText( ));    vj.sub.-- comp.setComponent((Component)t);    vj.sub.-- comp.setComponentURL(url.sub.-- name);    vj.sub.-- comp.setComponentInfo(info.sub.-- name);    vj.sub.-- comp.VJNodeInit(false,i,j,true);    vj.sub.-- comp.addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOut    put,    VJPort.SouthCenter); // Pin 0    vj.sub.-- comp.setXPt(0,getXPt(0)+40);    vj.sub.-- comp.setYPt(0,getYPt(0)+40);    vj.sub.-- comp.setImages(normalImage,selectedImage); // Pass references    to the static images down to the node    vj.sub.-- comp.nodeRect = new Rectangle(i-3,j-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);    vj.sub.-- comp.setSelected(true);    vj.theDocument.add(vj.sub.-- comp.comp);    vj.sub.-- comp.comp.validate( );    vj.sub.-- comp.comp.reshape(comp.bounds( ).x+50,comp.bounds( ).y+50,    comp.bounds( ).width,comp.bounds( ).height);    vj.sub.-- comp.comp.show( );    return vj.sub.-- comp;     } catch(Exception e) {     System.out.println(e);     return null;     }    }    public static void getImages(GIFFactory f){    normalImage = f.GetGIF(out);    selectedImage = f.GetGIF(in);    }    // Component Initialization    public void VJTextFieldInit(int x.sub.-- pt, int y.sub.-- pt) {     try {    String theText = new String("TextField    "+String.valueOf(instanceCount++));    text = new AWTTextField(theText,this);    text.setFont(new Font("Courier", Font.PLAIN, 14));    setNormalIcon(out);    setSelectedIcon(in);    setName(theText);    setComponent((Component)text);    setComponentURL(url.sub.-- name);    setComponentInfo(info.sub.-- name);    VJNodeInit(false,x.sub.-- pt,y.sub.-- pt,true);    addPort(port0.sub.-- info,port0.sub.-- name,VJPort.InputOutput,    VJPort.SouthCenter); // Pin 0    setImages(normalImage,selectedImage); //Pass references to the    static images down to the node    nodeRect = new Rectangle(x.sub.-- pt-3,y.sub.-- pt-3,    selectedImage.getWidth(vj.theContainer.theDesktop.vp.sub.-- w)+3,    selectedImage.getHeight(vj.theContainer.theDesktop.vp.sub.-- w)+3);     } catch(Exception e) {     System.out.println(e);     }    }    public void request(int port,int time) { }    public int componentID( ) {return 3;}    public void disconnecting(int port) {    send.sub.-- index= -1;    }    public void connecting(int port) {     request.sub.-- index=0;     send.sub.-- index = 0;     vj.request(0,request.sub.-- index++,this);    }    public void load(String s) {    StringTokenizer tokenStream = new    StringTokenizer(s,"@",false);           String data =    tokenStream.nextToken( ).replace(` `,`\t`).replace(`&`,` `);    if(data.startsWith(" ")) data = data.substring(1);    text.setText(data);           String family = tokenStream.nextToken( );    boolean bold =    Boolean.valueOf(tokenStream.nextToken( )).booleanValue( );    boolean italic =    Boolean.valueOf(tokenStream.nextToken( )).booleanValue( );    int size =    Integer.valueOf(tokenStream.nextToken( )).intValue( );    int theStyle = Font.PLAIN;    if(bold) theStyle = theStyle+Font.BOLD;    if(italic) theStyle = theStyle+Font.ITALIC;    text.setFont(new Font(family, theStyle, size));           if(|vj.isMicrosoft)    vj.doResize(this,text.size( ).width ,text.size( ).height);    }    public String save( ) {    String family = text.getFont( ).getName( );    int size = text.getFont( ).getSize( );    boolean bold = text.getFont( ).isBold( );    boolean italic = text.getFont( ).isItalic( );    return text.getText( ).replace(`    `,`&`).replace(`\t`,` `)+"@"+family+"@"+bold+"@"+italic+"@"+size    ;}    public void set(Object o,int port,int time) {    boolean ok = false;    if(o instanceof Color) {text.setForeground((Color)o); ok=true;}    if(o instanceof String) {text.setText((String)o); ok = true;}    if(o instanceof Long)    {text.setText((String)(((Long)o).toString( )));    ok = true;}    if(o instanceof Double) {    text.setText((String)(((Double)o).toString( ))); ok = true;}    if(o instanceof Float)    {text.setText((String)(((Float)o).toString( )));    ok = true;}    if(o instanceof Integer) {    text.setText((String)(((Integer)o).toString( ))); ok = true;}    if(o instanceof Boolean) {    text.setText((String)(((Boolean)o).toString( ))) ; ok = true;}    if(ok) {     // System.out.println(name + "has input at "+    String.valueOf(time)+" = "+ getText( ));     if(time<199) vj.request(0,request.sub.-- index++,this);    }    ok = false;    }     public boolean handleEvent(Event e) {    if(e.id == 1001) {    if(send index>=0)    vj.set((Object) text.getText( ),0,send.sub.-- index++,this);    }    switch(e.id){     case VJEvent.DOUBLECLICK: propertiesEditor( ); break;     // case 0: set(e.arg,0); System.out.println("GOT TF 0    "+e.toString( )); break;    }    return false;    }    public void propertiesEditor( ) {     if(edit==null){    edit = new textfieldEditor((Frame)(vj.theFrame),this);    edit.pack( );    edit.resize(12*32,6*32);    edit.show( );     }    }    public void init( ){ };    public void start( ){ };    public void stop( ){ };    public void destroy( ){ };    } // end class VJButton    class textfieldEditor extends Frame    {    VJTextField vjtf;    TextField tf;    Button ok;    Button cancel;    Choice fonts;    Font compFont;    Checkbox bold;    Checkbox italic;    TextField size;    String fontnames  !;    boolean dirty;     public textfieldEditor (Frame parent,VJTextField 1)     {    super("TextField Editor");    setBackground(Color.lightGray);     setLayout(new BorderLayout( ));    Panel p = new Panel( );    Panel centerPanel = new Panel( );    p.add(new Button("OK"));    p.add(new Button("Cancel"));    add("South",p);    vjtf = 1;    dirty = false;    Panel PN = new Panel( );    fonts = new Choice( );    fontnames = vjtf.text.getToolkit( ).getFontList( );    compFont = vjtf.text.getFont( );    for (int i = 0; i < fontnames.length; i++) {    fonts.addItem(fontnames i!);    if(fontnames i!.equals(compFont.getFamily( )))fonts.select(i);    }     fonts.setBackground(Color.lightGray);    bold = new Checkbox("Bold");    bold.setState(compFont.isBold( ));    italic = new Checkbox("Italic");    italic.setState(compFont.isItalic( ));    size = new TextField(String.valueOf(compFont.getsize( )));    tf = new TextField(vjtf.text.getText( ));     centerPanel.setLayout(new GridLayout(2,3));     centerPanel.add(new Label("Fonts"));     centerPanel.add(new Label("Text"));     centerPanel.add(new Label("Font Size"));    centerPanel.add(fonts);    centerPanel.add(tf);    centerPanel.add(size);    Panel textP = new Panel( );    textP.add(bold);    textP.add(italic);    PN.add(textP);    add("North",PN);    add("Center",centerPanel);    }    public boolean handleEvent(Event evt)    {  // System.out.println(evt.toString( ));    switch(evt.id){     case Event.ACTION.sub.-- EVENT:    {     if("OK".equals(evt.arg))     {    int theStyle = Font.PLAIN;    if(bold.getState( )) theStyle = theStyle+Font.BOLD;    if(italic.getState( )) theStyle = theStyle+Font.ITALIC;    vjtf.text.setFont(new Font(fonts.getSelectedItem( ),    theStyle, Integer.valueOf(size.getText( )).intValue( )));    vjtf.text.setText(tf.getText( ));    if(|vjtf.vj.isMicrosoft)    vjtf.vj.doResize(vjtf,vjtf.c.sub.-- width,vjtf.c.sub.-- height);             dispose( );             return true;           }    if("Cancel".equals(evt.arg))    {           dispose( );           return true;    }    return false;    }    default:           return false;    }    }    }    The AWTTextField.Java is as follows:    import java.awt.*;    public class AWTTextArea extends TextArea {     VJTextArea vjt;     public AWTTextArea(String n,VJTextArea v){    super(n);    vjt = v;    setFont(new Font("Courier", Font.PLAIN, 14));     }     public boolean handleEvent(Event e) {    return vjt.handleEvent(e);     }    }    ______________________________________

In this example, interconnections are made by mouse click, drag and dropoperations as follows. The output of scrollbars 1306 and 1308 areconnected to the bicopy objects 1308 and 1314 respectively. That valueis passed from bicopy object 1308 to splitter 1402 and text fieldrepresentation 1604 and from bicopy object 1314 to splitter 1404 andtext field representation 1606. In addition, the output of splitter 1402is coupled to the input of calculator 1502a while the output of splitter1404 is coupled to the input of calculator 1502b. Finally, the outputsof calculators 1502a and 1502b are respectively connected to the inputsof splitters 1402 and 1404. Thus, when scrollbar 604b is moved to a newposition, the value of that position is transmitted by the scrollbarobject 1306 to bicopy object 1308 and from there to text field componentrepresentation 1604. This means that the text fields 1602 and 1603 bothdisplay the changing values for their associated scrollbars 604b and1102 when either one of them is moved to a new position.

It is rather important to note that the interconnections described abovebetween objects on the logical view are subject to type andfunctionality checking in a dynamic manner when they are attempted.Thus, the connection in FIG. 16 that was made between the output port ofsplitter 1402 and the input port of calculator 1502a is functionallypermissible and was permitted to be made in a manner that wastransparent to the user. Conversely, if an attempt had been made toconnect the output port of splitter 1402 to the output port ofcalculator 1502a, that attempt would have been denied as functionallyimpermissible. In a similar manner, had an attempt been made to theoutput of calculator 1502a to the input of text label object 1304, thatconnection would have been denied since the input type (a value ornumber) was mistyped as an input to text label object 1304 which onlyaccepts input of type char or a string of characters. This functionaland type compatibility checking is performed by the VJDesktop code asset forth above.

The port or netpin type verification works in the following functionalmanner. When a component or object pin is created by being dropped ontothe logical view desktop 402, its presence there and the number andnature of its pins, if any, is logged, stored and tracked by theVJDesktop code. Specifically, the number and types of ports or netpinson the newly instantiated component or object is noted Once a componentor object having pins is instantiated, VJDesktop tracks and stores thestatus of its ports by polling them periodically as depicted by block1620 in FIG. 16A. The same is true for variables, the information forwhich is initially stored when a component that can pass, duplicate ormanipulate a variable is instantiated.

As used herein, the term "initiate a connection" means that the mousehas been clicked over only one port in preparation for tacking the linethat appears to another port. Once that other port is clicked on, theconnection is deemed to be completed.

Decision block 1622 is advised by block 1620 whether or not a connectionto one of the ports has been initiated. If no attempt to initiate aconnection has been made, polling continues. If a connection has beeninitiated, the type of port involved (input, output or bidirectional)and, if known, the type of variable expected (character, float, longinteger, short integer, string, etc.) on that port are stored as perblock 1624 with VJDesktop and control waits for completion of aconnection for the involved port while polling continues for theremaining ports.

Decision block 1626 sends control back to polling if the pendingconnection has not yet been made. If the connection is completed,control for the ports involved is passed to decision block 1628 whichdecides if the attempted complete connection between the ports involvedis valid. The type of ports involved and their functional affinity foreach other will be checked and verified. Connections directly between aninput port on one component will not be allowed to an input port onanother component nor will a direct connection between an output port ona first container to an output port on a second container. Alsoforbidden are connections between ports on the same component regardlessof their type.

In addition to checking that interport connections are valid, decisionblock 1628 also ascertains if the variable to be transmitted across thenew connection is valid for both ports. By referring to the storedcomponent and object port information, it can be determined, forexample, that the variable at the output of calculator 1502a in FIG. 16is mistyped as to the variable expected at the input of label 1304, acharacter or string. As a result, when that otherwise valid output toinput connection is attempted, it would be prevented by decision block1628 because of a variable type mismatch.

When the attempted connection is invalid, an error message will be sentto the screen for the user to see and notification is sent to block 1620to keep on polling for completion of the initiated, but not completedconnection. If the attempted connection is valid, it is completed andalso reflected on the display and the polling block 1620 is so advised.The stored port information is updated and the system waits for the nextattempted connection. If a completed connection is ended, decision block1634 is so advised by polling block 1620 and the stored type informationfor that connection is appropriately adjusted to reflect that the portswhich were involved in the ended connection are now free for other use.

FIG. 17 shows the final result of the coupled scrollbars with correctFahrenheit and Centigrade temperatures shown in text fields 1602 and1603, respectively. With both scrollbars at their minimum positions, theCentigrade scrollbar 604b position produces the value 0 in text field1602. In similar fashion, scrollbar 1102 produces a value of 32 in textfield 1603. If scrollbar 604b is pulled down to position 1702 where ithas a value of 80, as will then be displayed in text field 1602, thenscrollbar 1102, because of what are essentially feedback connectionsmade in FIG. 16, will move to position 1704 which will cause text field1603 to then display its corresponding value of 176 degrees. Because ofthe cross coupling described in connection with FIG. 16, movingscrollbar 1102 first to a position of 176 would cause scrollbar 604b tobe positioned at the point that represents the value 80, which would bedisplayed in text field 1602.

    ______________________________________    import java.net.*;    import java.io.*;    import java.util.Vector;    class ServerConnection extends Thread    private Socket                 .sub.-- mysocket;    private PrintStream                 .sub.-- output;    private DataInputStream                   .sub.-- input;    String id;    ConnectionManager creator;    int intId;    private Socket some.sub.-- server = null;    private DataInputStream in;    private PrintStream out;    private int clientType;    theClient XXXXserver;    private void doServerWork( )    {     Parser p;     String temp;     String command;     while(true){     while(|inputWaiting( ))           Thread.yield( );     String s = receive( );    // Dump a copy of rec input to console to see waht is happening    // uncomment next line in development    // System.out.println(id + "-->" + s);    // Parse the input string     p = new Parser(s);    // determine the command recieved from the client    command = p.arg(0);    if(|p.isValid( )){    send("--" + command);    }    else if(command.compareTo("Confirm") == 0){    send("--" + command + "confirmed");    }    else if(command.compareTo("SendAll") == 0){    creator.sendToAll(intId +"-->" + p.arg(1));     send("--" + command + "confirmed");    }    else if(command.compareTo("Connect") == 0){     send(handleConnect(p, s));    }    else if(command.compareTo("Command1") == 0){     send(handleFileServer(p, s));    }    else if(command.compareTo("Command2") == 0){     send(handleFileServer(p, s));    }    else if(command.compareTo("Command3") == 0){     send(handleFileServer(p, s));    }    else if(command.compareTo("Command4")== 0){     send(handleFileServer(p, s));    }     // Add more commands as required    else{    send("--Unknown request - " + command);    }  }    }    private String handleFileServer(Parser p, String s){    String command = p.arg(0);    XXXXserver.send(s);    return XXXXserver.receive( );     }     public DataInputStream getDataInputStream( ){    return in;     }     public PrintStream getPrintStream( ){    return out;     }     public void handleMessage(String s){     }    private String handleConnect(Parser p, String s){     if(initSocket(p.arg(1),Integer.valueOf(p.arg(2)).intValue( ))){     clientType = TypesOfClients.CONNECTED.sub.-- CLIENT;    XXXXserver = new theClient(this);    return("--" + XXXXserver.receive( ));    }    clientType = TypesOfClients.NORMAL.sub.-- CLIENT;    return ("--Failed connecting to "+ p.arg(1) + ":" + p.arg(2));     }    private boolean initSocket(String addr, int port){    try{    some.sub.-- server = new Socket(addr, port);    in = new DataInputStream(some.sub.-- server.getInputStream( ));    out = new PrintStream(some server.getOutputStream( ));    }    catch(Exception e){    try    {    some.sub.-- server.close( );    }    catch(Exception e2)    {    System.err.println ("Exception:\n" + e);    return false;    }    return false;    }    return true;     }    public ServerConnection(Socket s, ConnectionManager c, int    id1)    {    .sub.-- mysocket = s;    creator = c;    intId = id1;    clientType = TypesOfClients.NORMAL.sub.-- CLIENT;}    public boolean send(String s){    System.out.println("Sending" + s);    try{     .sub.-- output.println(s);    }    catch(Exception e){     return false;    }    return true;    }    private String receive( ){    try{    return input.readLine( );    }    catch(Exception e){    }    return " ";    }    private boolean inputWaiting( ){    try{     return (.sub.-- input.available( ) |= 0);    }    catch(Exception e){    }    return false;    }    public void run( )    {    id = .sub.-- mysocket.getInetAddress( ) + ":" +    .sub.-- mysocket.getPort( );    System.out.println("New Client : " + id);    try    {    .sub.-- output = new    PrintStream(.sub.-- mysocket.getOutputStream( ));    .sub.-- input = new    DataInputStream(.sub.-- mysocket.getInputStream( ));    send("Your id is" + intId);    doServerWork( );    .sub.-- mysocket.close( );    }    catch (Exception e)    System.err.println("Exception:\n" + e);    }    System.out.println("Disconnecting:" + id);    stop( );    }    }    class TypesOfClients{     static int NORMAL.sub.-- CLIENT = 1;     static int CONNECTED.sub.-- CLIENT = 2;    }    class Parser{     String args  ! = new String 10!;     int n;     boolean valid;    public Parser(String s){    if (parse(s))    valid = true;    else    valid = false;    }    public boolean isValid( ){     return valid;    }    public String arg(int i){     if(i <= n)    return args i!;     else    return " ";    }    public int getNumberOfArgs( ){     return n;    }    private boolean parse(String s){    String out = " ";    int i = 0;    int commas  ! = new int 10!;    int start, end;    int count = 0;    int openingB = s.indexOf("(");    if(openingB == -1){    args 0! = "No Opening Parantheses";    n = 1;    return false;    }    int lastPos = openingB;    args count! = s.substring(0, lastPos);    out = out + "{" + args count! + "}";    count = count + 1;    boolean GoOn = true;    while(GoOn){     start = s.indexOf(" ", lastPos);     if(start == -1){    GoOn = false;    }    else{     end = s.indexOf(" ", start+1);    if(end == -1){    args 0! = "Unmatched apostrophes";    n = 1;    return false;    }    commas i! = s.indexOf(",", end+1);    if(commas i! == -1){    commas i! = s.indexOf(")", end+1);    if(commas i! == -1){            args 0! = "Something's wrong";            n = 1;            return false;    }    }    args count! = .s.substring(start + 1, end);    out = out + "{" + args count! = "}";    count = count + 1;    lastPos = commas i!;    i = i +1;    }    }    System.out.println(out);    n = count;    return true;     }    }    // This is the MAIN routine for the server    // It initializes on a predetermined socket port. There can be many    // sockets for a particular computer that may have a unique IP    address.    // In this case port # 4000    // The corresponding collaborative component must use this    // socket to communicate with this server    // You must make sure that no other services are using this    // socket number.    class GenericServer    {    private static final int DEFAULT.sub.-- PORT=4000;    private ConnectionManager cm = null;    public GenericServer(int port)    {    System.out.println("Server using port" + port);    cm = new ConnectionManager(port);    cm.start( );    }    public static void main(String args  !)    {    int server.sub.-- port;    try    { // See if the user is using a commandline argument    to    // choose a different port for the service    server.sub.-- port = Integer.parseInt(args 0!,10);    }    catch(Exception e)    {    System.out.println("Defaulting to port" +    DEFAULT.sub.-- PORT);    server.sub.-- port = DEFAULT.sub.-- PORT;    }    new GenericServer(server.sub.-- port);    }    }    // Wait for a connection then act on it    class ConnectionManager extends Thread    {    private static int.sub.-- port;    private static Vector .sub.-- my.sub.-- threads = new Vector(5,2);    private ServerSocket .sub.-- main.sub.-- socket = null;    public ConnectionManager(int port)    {    .sub.-- port    = port;    }    public void run( )    {    serveRequests( );    }    public void sendToAll(String msg){     ServerConnection s;     for(int i = 0; i < .sub.-- my.sub.-- threads.size( ); i++){    s = (ServerConnection) (.sub.-- my.sub.-- threads.elementAt(i));    // For each client connected send out message    s.send(msg);     }    }    private void serveRequests( )    {    try {.sub.-- main.sub.-- socket = new ServerSocket(.sub.-- port);}    catch(Exception e) {System.err.println(e); System.exit(1);}    ServerConnection temp.sub.-- sc = null;    System.out.println(.sub.-- main.sub.-- socket.toString( ));    while (true)    {           try           {             Socket this.sub.-- connection =    .sub.-- main.sub.-- socket.accept( );             temp.sub.-- sc = new    ServerConnection(this.sub.-- connection, this, .sub.-- my.sub.-- threads.s    ize( ));             temp.sub.-- sc.start( );             .sub.-- my.sub.-- threads.addElement(temp.sub.-- sc);             // clean up the vector if needed             for(int    i=0;i<ConnectionManager..sub.-- my.sub.-- threads.size( );i++)    if(|((ServerConnection) (.sub.-- my.sub.-- threads.elementAt(i))).isAlive(     ))                  .sub.-- my.sub.-- threads.removeElementAt(i);    }    catch(Exception e)    {             System.err.println("Exception:\n" + e);    }    }    }    }    ______________________________________

As described above, the VJ Tool provides a live development or authoringenvironment in which socialization among objects or components can occurimmediately upon their creation or instantation without any wait to planor test their integration. For example, as shown in FIG. 16, once theoutput of bicopy object 1308 was connected to text field representation1604, the output value of scrollbar 1306 was displayed in the physicalview 500. If this result is not what was desired, the user can changethe connection or add another component on the fly without having todebug code or review a flowchart. Similarly, when the output of splitter1404 is connected to the input of calculator 1502b and displayed viatext field representation 1606, the user is able to make an immediatedetermination that the conversion calculations are correct and that thedisplayed arrangement is satisfactory. In other words, being able tomake connections on the fly immediately proved or disproved the resultsobtained because VJ Tool creates a "live" environment wherein appletdesign creation and trial are integrated so that the result is thenplayed out virtually simultaneously with creation. This is analogous tobuilding a hardware prototype or test board by connecting, disconnectingand moving components around the board while the power is on|

Component 542 of FIG. 5 is a folder component in which associatedcomponents can be stored to act as templates for other applets to bedesigned in the future. Say, for example, that a user had designed thespecific arrangement shown in FIG. 16 and dragged it as a componentassembly into an object folder instantiated from folder 542. That objectfolder can later be opened and the component assembly stored therein bereused or its calculators modified to display Centigrade versus Kelvinor with slightly more modification to the text and label fields, feetversus meters. In fact, a hierarchy of folders can be built up in thismanner. Unlike ordinary folders which are static and store only filesthat can be copied in an ordinary fashion, component folder 542 actuallystores parts or all of a program with its interconnections intact.

To build a hierachial component, a component is instantiated on alogical or physical display. Then, a hierarchial component folder isselected and instantiated on the display. The customization (edit)window is completed to reflect an appropriate name for the particularcomponent folder and the customization window is closed. Another windowis presented for receipt of one or more components and their connectionsto capture and create the "hierarchial component." Thus, the hierarchialcomponent acts as an organizer to capture debugged logic and make itavailable to other applets without modification.

There are several kinds of components in VJ Tool. For example, as shownin FIG. 5, there is a GUI primitive such as 508, a primitive spreadsheet524, a primitive backend component 570 (calculator) and a backendcomponent 558 (splitter). In addition, some of the components have theability to be made collaborative, that is, they can interact with eachother to show or indicate interdependencies. For example, if three usersare working with collaborative spreadsheets, a change made by one userwill also be reflected in the spreadsheets of the other two users. Thismakes it easy to keep all members of a team current with respect tochanges in spreadsheet information. Under VJ Tools, collaborativecomponents work as follows.

To begin the collaboration process, a standard VJ Tool component, suchas a spreadsheet 524, is created from the physical view palette of VJTool, see FIG. 5. As shown in FIG. 18, there would be a copy, 524a, 524band 524c, of each spreadsheet object instantiated for each client user,1806a, 1806b and 1806c, that wanted their spreadsheet to becollaboratively coupled to other spreadsheets. Collaboration can beextended to the entire spreadsheet or it can be limited to designatedcells in the spreadsheet. For example, individual cells in eachspreadsheet can be collaborated by simply clicking on them or the entirespreadsheet can be collaboratively coupled by simultaneously pressingthe <CONTROL> key while clicking on any portion of the spreadsheet. Itis also possible to have two collaborating spreadsheets completelylinked to each other while one of these is linked to a third spreadsheeton a designated cell basis only.

All such standard components to be collaborated are augmented with codethan connects them to a VJ Spreadsheet Server, a Java application, thatis running on the same HTTP server as the VJ Tool applet. VJ SpreadsheetServer is responsible for managing the collaboration. This arrangementis necessitated by the fact that this is the only way a Java applet,when VJ Tool is implemented as a Java applet, can interact with a Javaserver application through a designated socket.

The clients, 1808a, 1808b and 1808c, are typically connected across theInternet 1810 to an HTTP server 1802. The HTTP server 1802 can includemany applications and applets and it often does, but for the sake ofclarity there are only three applications, 1804a, 1804b and 1804c, andthree applets, 1806a, 1806b and 1806c, shown. Application 1804c,designated for purposes of this explanation as the Java Server, isusually a daemon server, has full access to the underlying file systemand can be used to communicate with related servers, not necessarilyJava servers, on the Internet.

In the simplest mode, collaborative capable components, are associatedwith one or more Java servers running on the same HTTP server thathouses and services the VJ Tool applet. As each instance of suchcomponents are created and deployed in the VJ Tool environment, andcollaboration is desired, each collaborative component to be isregistered with the Java server, in this case 1804c. The process ofregistration builds an instance 1812a of the registering component 524ain Server 1804c. It will also build a similar instance of the othercomponents involved, 1812b and 1812c, as they are registered. Onceregistered with the Java Spreadsheet Server 1804c, the component, assumeit's 524a for purposes of this discussion, sends out information toServer 1804c based on interactions with the user and possibly otherregistered components, 524b and 524c, in the deployment environment;that is; other collaborative components to which a changing component istied. In addition, the collaborated component 524a will receiveinformation from Server 1804c which it may choose to use as feedback tothe user or to the other collaborated components with which it is soassociated. Basically, the message set "Publish cell", "Unpublish cell"and "Update cell" is used to alter cell content.

However, each time the collaborative arrangement is initialized, nothingis shared between the collaborated components unless the state of thelast session was saved and reloaded at initialization into SpreadsheetServer 1802. Since the registration process builds a record in Server1804c of which portions of which collaborated components are coupled, itis relatively straightforward for the Server to accumulate thisinformation from a changed component, which utilizes a publish messageto send it there and then republish or broadcast it to the othercollaborated components to effect updating, thereby making it public.Thus, nothing is seen by any of the unchanged collaborated componentsuntil the Spreadsheet Server 1802 has relayed the changed information onto them.

A flowchart of the collaboration process is illustrated in FIG. 19. Whena new component is created as in block 1902, the user is asked bydecision block 1904 if the new component should be collaborative. Ifnot, the user and VJ Tool go off via block 1906 and do something else.If the user responds in the affirmative to the query of block 1904, thecomponent properties are examined to determine if this specificcomponent can be collaborated by decision block 1908. If collaborationisn't possible, control is passed to block 1910 which sends anappropriate message to the user and then waits for the user to makeanother request.

If a new component can be collaborated, it is registered with a Javaserver as shown in function block 1912. The server, as indicated byblock 1914, then builds an instance of the registering component inorder to know which components it is responsible for. In addition,pursuant to block 1916, the server builds a record listing thoseportions, some or all, of the registered components which are linked orcollaborated. Once that identity and designated linked portions of thecomponents have been identified and recorded, the server changes theinfirmation in the collaborated portions when it receives informationfrom a component as shown in block 1918 and broadcasts the changedinformation to the other collaborated components via block 1920.

Collaboration within the VJ Tool, in accordance with the foregoingdescription, is accomplished utilizing the source code presented below.

    ______________________________________    import java.awt.*;    import java.net.*;    import java.io.*;    public class VJChat extends TextArea implements VJContext {    static String info.sub.-- url = "VJChat.html";    static String quick.sub.-- info = "Chat component - chat to others using    VJ specify user name by doubleclicking icon";    static String port.sub.-- name  ! = {"send in","send out"};    static String ports.sub.-- info  ! = {"messages to send to chat (attach    to    textField)","all incoming messages (attach to textarea)"};    static int port.sub.-- type  ! = {VJPort.Input, VJPort.Output};    static int port.sub.-- location  ! = {VJPort.NorthCenter,    VJPort.SouthCenter};    static int numberOfPorts = 2;    static Image normalImage;    static Image selectedImage;    private auxClient client;    static int instanceCount = 0;    // Instance specific attributes    String name;    // To send messages to the visualJava kernel    visualJava vj;     public VJChat(visualJava v){    super( );    vj = v;    client = new auxClient(this, vj);    client.startUp( );    name = new String("Chat"+String.valueOf(instanceCount++));    public static void getImages(GIFFactory f){    normalImage = f.GetGIF("chat.gif");    selectedImage = f.GetGIF("chat.gif");    }    String clientname = new String(" ");    public void setName(String s){     clientname = s;     client.write("SetName(\" " + clientname + "\")");    }    public void handleMessage(byte msg  !){    try{    String s = new String(msg, 0);    if(|s.startsWith("--")){     s = s.substring(0, s.indexOf("zzyx"));    // Output the message rec from the SERVER on port 1    // So you can see what is being chatted about|    vj.set((Object)s, 1, send.sub.-- index++, (Component)this);     }     }    catch(Exception e){ };    }    public boolean editorOpen = false;    public void propertiesEditor( ) {     if(|editorOpen){    propsEditor edit = new propsEditor((Frame)(vj.main.sub.-- w),this);    edit.pack( );    edit.resize(4*32,4*32+10);    edit.show( );    editorOpen = true;     }    }    public void reset( ) { }    public String portName(int port){return port.sub.-- name port!;};    public String portInfor(int port){return ports info port!;};    public String nodeInfo( ){return quick.sub.-- info; };    public String authorName( ){return new String("The Duke's    Girlfriend");};    public String expirationDate( ){return new String("8/10/97");};    public String cost( ) {return new String("Demo");};    public String version( ){return new String("0.1");};    public boolean hasOwnThread( ) {return false;};    public String componentURL( ) {return info.sub.-- url;}    public int componentID( ) {return 5556432;}    public void disconnecting(int port) { }    public void connecting(int port) { }    public void load(String s) {    }    public String save( ) {    return " ";}    int request.sub.-- index = 0, send.sub.-- index = 0;    public void run( ) {                  request.sub.-- index=0;    send.sub.-- index=0;           vj.request(0,request.sub.-- index++,this);    }    public void request(int port,int time) {    }    public void set(Object o,int port,int time) {     if(port= =0) {    try{    // Send the message rec on input port 0 to server for    distribution to all    // other connected clients    client.write("SendAllClients(\" " + (String)o    + "zzyx\")");    }    catch(Exception e){    }    }    vj.request(0,request.sub.-- index++,this);    }    public String name( ) {return name;}    public void init( ){ }    public void start( ){ };    public void stop( ){ };    public void destroy( ){ };    public Image getNormalImage( ) {return normalImage;}    public Image getSelectedImage( ){return selectedImage;};    public int numberOfPorts( ){return numberOfPorts;};    public int numberOfConnections( ){return 0;};    public int portType(int i){return port.sub.-- type i!;};    public int portLocation(int i){return port.sub.-- location i!;};    public boolean handleEvent(Event e) {    switch(e.id){    case VJEvent.DOUBLECLICK: propertiesEditor( ); break;    }    return false;    }    }    class propsEditor extends Frame    {    VJChat vjc;    TextField tf;    Button b;    Button cancel;     public propsEditor (Frame parent,VJChat c)     {    super("Enter name");    setLayout(new BorderLayout( ));    add("North",new Label("Name"));    vjc = c;    tf = new TextField(vjc.clientname);    add("Center",tf);    b = new Button("OK");    cancel = new Button("Cancel");    Panel sp = new Panel( );    sp.add(b);    sp.add(cancel);    add("South",sp);    }    public boolean handleEvent(Event evt)    { // System.out.printin(evt.toString( ));    switch(evt.id){    case Event.WINDOW.sub.-- DESTROY:    {    vjc.editorOpen = false;    dispose( );    return true;    }    case Event.ACTION.sub.-- EVENT:    {    if("OK".equals(evt.arg))    { vjc.editorOpen = false;    vjc.setName(tf.getText( ));    dispose( );    return true;    }    if("Cancel".equals(evt.arg))    { vjc.editorOpen = false;           dispose( );           return true;    }    return false;    }    default:    return false;    }    }    }    class auxClient{    private AAuxClient writer;    private DataInputStream in;    private PrintStream out;    private Socket server;    static int SERVER.sub.-- PORT = 4000;    VJChat creator;    visualJava vj;    public auxClient(VJChat t, visualJava v){     creator = t;    vj = v;     initSocket( );    }    public void startUp( ){     AAuxClient reader = new AAuxClient(this, in, out);      Thread t = new Thread(reader);      t.setPriority(Thread.MIN.sub.-- PRIORITY);     writer = new AAuxClient(this, in, out);      t.start( );    }    public void write(String s){    writer.send(s);    }    public void handleMessage(byte  ! b){     creator.handleMessage(b);    }    private void initSocket( ){     byte bytes  ! = new byte 4096!;     int c;     try{     server = new Socket(vj.getDocumentBase( ).getHost( ),    SERVER.sub.-- PORT);     in = new DataInputStream(server.getInputStream( ));     out = new PrintStream(server.getOutputStream( ));    }    catch(Exception e){     try{     server.close( );     }    catch(Exception e2){     System.err.println("Exception:\n" + e);     // System.exit(1);     }     // System.exit(1);     }    }    }    class AAuxClient implements Runnable    {    DataInputStream input = null;    PrintStream output = null;    auxClient creator;    boolean inputValid = false;    public AAuxClient(auxClient b, DataInputStream in,    PrintStream out){     creator = b;    input = in;    output = out;     }     public void run( ){    String msg;    int n;    byte  ! b = new byte 500!;    while (true){    try{    while(input.available( ) = = 0{     Thread.sleep(100);    }    }    catch(Exception e){     System.out.println ("IO exception in run( )");    }    b = receive( );    if(b.length = = 0)}     return;    }    service(b);     }     }    public boolean send(byte b  !, int length){     try{    output.write(b, 0, length);    output.flush( );    }     catch(Exception e){    return false;     }     return true;    }    public boolean send(String s){     byte  ! b = new byte 200!;     s.getBytes(0, s.length( ), b, 0);     return send(b, s.length( ));    }    private void service(byte msg  !){     creator.handleMessage(msg);    }    private byte  ! receive( ){     byte  ! b = new byte 200!;     try{     input.read(b);     }    catch(Exception e){     return new byte 0!;    }    return b;     }    }    ______________________________________

FIG. 20 illustrates a screen with the logical view in accordance with apreferred embodiment. A sound component 2000 has been instantiated onthe logical view by dropping a sound icon onto the logical desktop 2010.

FIG. 21 illustrates a screen with the logical and physical viewpreparing a hierarchical component in accordance with a preferredembodiment. A button 2120 has been instantiated and customized 2110 onthe logical desktop 2114 and its physical representation 2100 is alsoreflected in the physical desktop 2112.

FIG. 22 illustrates a screen with a connection made for playing a soundin accordance with a preferred embodiment. The button component 2200 isconnected 2210 to the sound component 2220 in the logical desktop 2230.The Play Sound Button component 2240 is the physical view in thephysical desktop 2250.

FIG. 23 illustrates an edit screen for a folder component utilized toprepare a hierarchical component in accordance with a preferredembodiment. A Container 1 folder 2300 is instantiated in the logicaldesktop 2350 by dropping a folder component 2360 on the desktop. Acustomize or edit window 2310 pops up when the folder is instantiated.This edit window can be utilized to change the name of the folder andthe number, location and type of active ports of the folder component.The Container 1 folder is logically represented by a window 2320 wherethe logic of the folder (hierachial component) can be created on the flyby adding or deleting components in the window 2320. The button 2330 isalso shown in the physical desktop 2340.

As shown in FIG. 23A, a folder class with options for unidirectional andbidirectional ports and an editor is first created as depicted by block2370. The user instantiates a folder component by dragging and droppingit onto the logical desktop 2350 as reflected by block 2372.

When the folder is instantiated and its edit window 2310 pops up, asdescribed above, the folder name and the number, location and type ofports can be selected or changed. This capability is reflected in block2374. Finally, as shown by block 2376, the folder component waits on theuser to indicate what other components, including other folders, shouldbe placed within it. This procedure is described hereafter in connectionwith FIG. 24.

FIG. 24 illustrates a hierarchical component creation customization inaccordance with a preferred embodiment. The button 2400 which wasoriginally in the logical desktop 2420 has been moved into the Container1 folder 2410. The internal connectors 2430C and 2440C are representedin the Container 1 folder 2410 and refer back to the logical desktopports 2440L and 2430L of the folder 2450 in the logical desktop 2420.The ports can be used to transfer information into and out of a folder2410. One of ordinary skill in the art will readily recognize that othercomponents could be added to the Container 1 folder 2410 to create amore complex hierarchical component which could even include nested andrecursive hierarchical components.

FIG. 25 illustrates the completed physical view of a hierarchicalcomponent in accordance with a preferred embodiment. The sound button2500 in the physical view 2520 is now inside the folder 2510 which canbe used to simplify complex logic on the logical desktop 2530 and reducescreen clutter. This technique can be utilized to capture debuggedcomponents and component assemblies in a single representation of manycomponents. Users can thus create their own components.

While the invention is described in terms of preferred embodiments in aspecific system environment, those skilled in the art will recognizethat the invention can be practiced, with modification, in other anddifferent hardware and software environments within the spirit and scopeof the appended claims.

What is claimed is:
 1. A method of creating an object oriented componenthaving multiple bidirectional ports, the component being used inassociation with an object oriented applet or application, comprisingthe steps of:a) initializing the component ports to a predetermined typeand value; b) polling the ports to ascertain whether an input has beenconnected to one of the ports; c) identifying the type and value of theinput once it is coupled to a port; and d) setting all the remainingports to output the same type and value as that of the input.
 2. Themethod according to claim 1 which comprises the additional steps ofchecking to see if the component has a previously saved state prior tothe initializing step and initializing its ports to the state type andvalue rather than the predetermined type and value if it does.
 3. Themethod according to claim 2 which comprises the additional steps ofdetermining if the input type and value has been removed andreinitializing all of the ports of the component to the predeterminedtype and value if it has.
 4. The method according to claim 3 whichcomprises the additional steps of determining if the input type andvalue has been removed and maintaining the other ports at the same typeand value as that of the input if it has not.
 5. The method according toclaim 1 which comprises the additional steps of determining if the inputtype and value has been removed and reinitializing all of the ports ofthe component to the predetermined type and value if it has.
 6. Themethod according to claim 5 which comprises the additional steps ofdetermining if the type and input value has been removed and maintainingthe other ports at the same type and value as that of the input if ithas not.
 7. The method according to claim 1 which comprises theadditional steps of determining if the type and input value has beenremoved and maintaining the other ports at the same type and value asthat of the input if it has not.
 8. A system for creating an objectoriented component having multiple bidirectional ports, the componentbeing used in association with an object oriented applet or applicationsaid system comprising:a) an initializer that sets the component's portsto a predetermined type and value; b) a poller that continuously checksthe ports to ascertain whether to an input has been connected to one ofthe ports; c) an identifier that establishes and saves the type andvalue of the input once it is coupled to a port; and d) a duplicatorthat sets all of the remaining ports to output the same type and valueas that of the identified input.
 9. The system according to claim 8which additionally comprises a verifier that checks to see if thecomponent has a previously saved state prior to its being initializedand what the state type and value is if a saved state is found and asecond initializer to set the components ports to the state type andvalue rather than the predetermined type and value if a saved state isfound.
 10. The system according to claim 9 which additionally comprisesa second poller that determines if the input has been removed andrequests the initializer to reinitialize all of the ports of thecomponent to the predetermined type and value if it has.
 11. The systemaccording to claim 10 which additionally comprises a second poller thatdetermines if the input has been removed and requests the initializer toreinitialize all of the ports of the component to the predetermined typeand value if it has not.
 12. The system according to claim 8 whichadditionally comprises a second poller that determines if the input hasbeen removed and requests the initializer to reinitialize all of theports of the component to the predetermined type and value if it has.13. The system according to claim 12 which additionally comprises asecond poller that determines if the input has been removed and requeststhe initializer to reinitialize all of the ports of the component to thepredetermined type and value if it has not.
 14. The system according toclaim 8 which additionally comprises a second poller that determines ifthe input has been removed and requests the initializer to reinitializeall of the ports of the component to the predetermined type and value ifit has not.
 15. A computer program embodied on a computer-readablemedium for creating an object oriented component having multiplebidirectional ports, the component being used in association with anobject oriented applet or application, said embodied programcomprising:a) first software that initializes the component ports to apredetermined type and value; b) second software that polls the ports toascertain whether an input has been connected to one of the ports; c)third software that identifies the type and value of the input once itis coupled to a port; and d) fourth software that sets all the remainingports to output the same type and value as that of the input.
 16. Thecomputer program embodied on a computer-readable medium as recited inclaim 15 which additionally comprises fifth software for checking to seeif the component has a previously saved state prior to its beinginitialized, means for determining what the state type and value is andmeans for initializing the components ports to the state type and valuerather than the predetermined type and value if it does.
 17. Thecomputer program embodied on a computer-readable medium as recited inclaim 16 which additionally comprises sixth software for determining ifthe input type and value has been removed and reinitializing all of theports of the component to the predetermined type and value if it has.18. The computer program embodied on a computer-readable medium asrecited in claim 17 which additionally comprises seventh software fordetermining if the input type and value has been removed and maintainingthe other ports at the same type and value as that of the input if ithas not.
 19. The computer program embodied on a computer-readable mediumas recited in claim 15 which additionally comprises fifth software fordetermining if the input type and value has been removed andreinitializing all of the ports of the component to the predeterminedtype and value if it has.
 20. The computer program embodied on acomputer-readable medium as recited in claim 19 which additionallycomprises sixth software for determining if the input type and value hasbeen removed and maintaining the other ports at the same type and valueas that of the input if it has not.
 21. The computer program embodied ona computer-readable medium as recited in claim 19 which additionallycomprises fifth software for determining if the input type and value hasbeen removed and maintaining the other ports at the same type and valueas that of the input if it has not.